i know merc asked me a question like this once but i can't find it, but it was along the lines of: "how would zevran and lucanis get along in datv" and it's a question that's been haunting me for all of my datv zev pt
bc on the one hand, it's really hard to put zev in datv. if you want the crows to be a meaningful faction at all, then you can't have zevran. he is a crow hunter at this point, he's not going to ally with them even a little bit.
and in theory that makes any sort of datv situation difficult, because even with end of the world scenarios, he's more likely to go off on his own and help in other ways, or join up with the inquisitor, or the hof, or any other number of people. because he just really fucking hates the crows.
lucanis is kind of the epitome of a crow to zevran. it's not the training, it's the house. he's a dellamorte. he's a multi-generational crow. he's in line for first talon. sure they both went through shitty childhoods, but lucanis is, from zevran's pov, content with the system and doesn't care to change it. he and his (his cousin, grandmother, teia, viago, crow rook, etc) are doing just fine. they're not being played against each other by talons in some sick political mind game. they're the ones benefiting from buying kids off the streets, pulling the strings to mess with their recruits, upholding and furthering the system. it doesn't matter how "good" they try to be, the crows are rotten from the core to zevran.
and on the flip side, zevran is everything lucanis loathes. he broke a contract. he went back on his word and betrayed his family. the crows are lucanis' family and no matter how much he may disagree with them or deplore the situations he gets put in because of them, he's never going to abandon his family. and someone who does leave their family like that turns his stomach. lucanis would rather die than abandon or break a contract, and that he mentions that as the reason the crows cannot go back to ferelden feels very telling.
i don't see an easy way for them to get past that except under highly specific circumstances, like if varric had contracted zevran's services to assist in stopping solas (in which, he doesn't see the contract closed just because he's in fade jail), or in some situation where his child is rook (like necromosss au). i think those situations are very few and far between, but i can see it happening.
in which case... i want to say they'll grow to like each other, i just don't know that it's really possible. i think they'd get along rather well if they were ever able to get past the crow trauma. i think in a scenario where lucanis was kicked out of the crows or left them, zevran would step up to help him as he's helped other crows escape the life. i think in any case, whether they come to like each other or not, they might be petty around the lighthouse, but professional in the field. and lucanis, while not externally, would definitely take to heart any of the critiques zevran has of the crows--lucanis isn't blind to their failures or shortcomings, he's just quietly critical whereas zevran is highly vocal at this point.
and of course, it would make my idea of lucanis hiring zevran at the end of datv to smuggle illario away from the crows all the more realistic, what with them having worked together before.