Yup - being a warlock should "dominate" your character, RP wise.
I think the celestial pack warlock can make sense if the player and DM work on it ... but it's the only one that makes such sense easily. And min-maxers want *hexblade*...
But paladins and oaths have divorced the paladin from the LG shackles, in 5e which we must be talking as hexblade right?
Don't there exist dieties that have some passing interest or affiliation with say fey like woodys stuff - that could fit the feylord?
Don't their exist deities with affiliations with shadow and that stuff too?
etc etc etc?
even some of the knowledge or explorer could be linked in theory to "old ones", right?
Which patrons in your view are absolutely complete incompatable with any deities so that religiously focused character could not be associating with them in some form of conjunction with or go between divine to devoted?
I did not take the "patrons" as singular unique entities - as in there is a single old one or a single fiend etc - but as representations of a type of entity. Did you take it differently? Are all warlocks of the fiend following a single fiend?