(A/N: I think people are missing the obvious points that I am mentioning, and I also wanted to show the timelines I have planned for them in a way. Personally speaking, I have no desire to write entire fanfics for each separate timeline as of now. But here is also some stuff that you need to take in account... and well there will be a bit of spoilers if you haven't understood the stuff that had been released already).
1) Priscilla Benedict/Priscilla Barielle/Priscilla Natsuki
Title: The Blazing Sun, Princess, The Bloody Bride(There are a few more titles, but if you are really into that much of word titles then you can just see fandom of every character) The First One, The Wife of the Radiant Moon.
Personality: Upto you to find out.
Abilities: Yang Sword(It cuts and then burns down whatever target the user has. While being weaker than Reid, it still has pretty much same affect but it does by 'Burning', Rather than 'Cutting on a conceptual level'. Currently no new usage other than it's cannon are shown)
Al Luxa(A boosting magic, that boosts all parameters of the target. Whether it was an originally created magic or an pre-existing magic remains unknown)
Asperia(A yang magic that creates solid constructs of light. It is highly probable to be an created magic utilizing pre-existing attributes of Yang Element and higher versions may exist)
Core Timeline Divergence: She accepts to help Subaru in her timeline for becoming a servant, it is both an unhighly probable scenario and a scenario that Priscilla Barielle may take. Despite admitting it was the greed of a pig, she decides to humour him on the condition for being a slave and that he will have only minimum support.
Core Timeline points: It can be seen that it is a much calmer version of her younger self, but also over-protective of her family. She still retains her core character traits however there maybe noticeable differences.
Aldebaran eventually betrays her and captures Subaru, it is unknown at what point of time it happened in previous loop, but it is highly suggested he uses Ol Shamak spell to seal Aldebaran forever.
She has shown immense grief and loss over her previous timeline family, and with her husband being only survivor of that memory, she may do whatever to retain him.
She knew about Subaru's return by death from previous timeline, it is unknown how she thought of that ability.
Her favourite English word to call Subaru is 'Darling', because according to her she is the blazing sun and Subaru is the radiant moon and darling words can be used for both parties, reflecting their chemistry.
2) Crusch Karsten/ Crusch Natsuki
Title: The Duchess, Valkyrie, The Second in charge(fanfic), Boss Lady(fanfic), Deadliest Sword(fanfic)
Personality: Upto you to find.
Abilities: Her canon abilities, and the Breathing Style(A type of hybrid ability which makes her natural limiters of body go off, and by further with the Flow method. The power level scales exponentially)
Core Timeline Divergence: It can be seen as alternate revenge if timeline where she is the sole survivor of the expedition, and is toyed by Greed and Gluttony, and with further loss of her name she is broken totally. Later Subaru takes her and considering he will need her power to take revenge they make an contract, where Subaru will be the one making all decisions.
Core Timeline Points: The Severe trauma makes her repulsed to everyone, including her own children, only except for Subaru.
Due to her condition she decides to seduce Subaru, which ends up resulting him breaking down their sexual intercourse, later taken by guilt and a desire to continue his life, he accepts Crusch as his romantic partner. Later they marry.
It is said she felt repulsed even to her children, while it is not defined how it resulted her relationship with Subaru and her children, but it can be taken as she has masochistic tendencies, and has a deranged line of thoughts.
It may be not possible to fix her unless one literally rewrites her mind/mind rapes her, considering she lived an entire life with Subaru but never healed.
Seems to be the only woman not to have realized about Subaru's return by death until now, stemming from her complete acceptance of Subaru rather than being incapable of deducing it.
Her favourite English word to call Subaru is 'My Lord' or 'My Liege', which are just english translations of what she usually calls him. Though she takes them as a scared words preferring the English version, also out of arrogance to be the unique subordinate of Subaru during their early years.
3) Anastasia Hoshin/ Anastasia Natsuki.
Title: Great Businesswoman/Greedy Merchant/ The Executioner.
Personality: Upto you to find.
Abilities: She seems to be capable of using magic(Not yet in rebooted timeline), although how strong of a magician she is remains unknown.
Core Timeline Divergence: Both of hers and Subaru's names are eaten, because Subaru was mistaken as a Witch-cultist and because of him supporting her claims in true identity, both of them were arrested, making her resent him. They were tortured by a maddened Felix, and Julius, they survived their period in the prison due to Subaru's contracted spirit and later escaped with his help, he also did his best to keep him and her alive in the frozen forests on the outskirts of Gusteko.
Core Timeline Points: Initially she hated Natsuki Subaru and only used him, but then she realized how he will be the only one who won't change unlike the rest of the world. Eventually they chose to marry each other, while it is unknown how deep their affection was at this point considering it is suggested they married out of necessity or perhaps to cope up with their trauma.
However after marriage, they seem to have fallen deeply in love with each other, especially Anastasia who loved her time with Subaru so much, experiencing a bliss that made her commit atrocious crimes or murders for petty reasons just so she can experience another day in this bliss.
Anastasia hates Julius and especially Emilia a lot for unknown reasons, however it can be suggested that Julius and Emilia were never married in this timeline as they were killed separately.
She has realized that Subaru had return by death due to various hints, however she never knew the clear nature of the power until she returned by death herself.
Her favourite word to call Subaru is 'Husband' as if to make him never forget his link to the other world, and she is shown to wear red lipstick because Subaru particularly likes them on her face.
4) Ram/Ram Natsuki
Title: The Oni God/Wifey(Fanfic).
Personality: Upto you to decide.
Abilities: She had shown no particular abilities, or whether her horn was fixed in her timeline like Anastasia's gate in hers, remains unknown.
Core Timeline Divergence: During Sanctuary events, Emilia and Rem die with her choosing to kill Roswaal over her feelings for him, later she survives and has shown to develop a relationship with Subaru. Later she started hating Roswaal due to what he did to them, especially her hubby on how he manipulated events keeping him on edge of death.
Core Timeline Points: Not much is known about this timeline, other than Ram died in her old age beside her husband and children. She is shown to be much more mature, and less keen on insulting others.
She seems to be broken down after realizing her husband had died many times to save her, making her wanting to save him by any means, that weren't stupid and would not make him suffer.
She calls Subaru 'Hubby', affectionately in english for no other particular reason that it sounds nice and is easier to pronounce than Husband, and Darling.
5) Theresia/ Theresia Natsuki
Titles: The Sword Saint/Flower Girl/Sword Saintness(Fanfic)/ Senorita(Fanfic)/ The betrayer(Fanfic)
Personality: Upto you to find.
Abilities: She is a corpse soldier and ordinary wounds cannot kill her. She is a possessor of 'Sword Icon', which is capable of cutting every concept, like REID however on a much more higher scale with the only disadvantage being her body and soul herself.
Core Timeline Divergence: Subaru had taught her Senorita song, which later the World or the Icon sang for them when the Icon bloomed in full strength(No, they didn't sing during the fight. It was world singing itself for them or the Icon making the world sing). It can be inferred that Natsuki Subaru is from 2019 or later due to him knowing Senorita Song, and it is unknown at what period of time or in which place he arrived in Od Laguna.
Core Timeline Points: He seems to been a member of the Witch Cult for unknown reason after arriving, he is also shown highly interested in Spanish and completely smitten by the song 'Senorita', in his timeline when it came out, though for reasons or what led it to happen to him remains unknown.
He then taught these words to Corpse Soldier Theresia, though it remains unknown for what were reasons behind it initially. It seemed as a Corpse soldier Theresia developed feelings for Subaru and when her soul was fixed upon Icon's descend to bear it's power, those feelings intensified.
At some point, she betrayed Wilhelm after Subaru tried to make them end up together by becoming a villain of sorts.
It is unknown whether she is original Theresia Van Astrea, or the Animated Corpse that became a person of their own with Theresia's memories, but at the very least they are shown to be very crazy for Natsuki Subaru.
Her favourite way of calling Subaru 'Senor', and she is shown to know spanish words.