Within the Germanic migrations, there had been Alans who also assimilated with them
Don't forget that Germanic peoples were importantly Sarmatized too, the Alan influence being more or less undistinguishable at this point.
What if Alans had been a recognizeable minority in certain areas in Western European kingdoms for centuries too come ?
Giving that Germanic peoples didn't became recognizeable minorities within Romania, I don't see how it could happen.
I should point you did have Alanic enclaves within Romania, notably around Orléans or other places in France that keep having a toponimic clue on their presence. They were eventually swallowed up by the Romano-Barbarian kingdoms.
Remember that Barbarian identity, originally, is esentially political : you're a Goth because you're part of the Gothic ensemble. Not because you're an Eastern German (Goths themselves are the result of an ethnogenesis, importantly influenced by Rome, of Germans, Proto-Slavs, Dacians, Sarmatians, Romans).
At best, you'd have a similar ethnogenesis at the benefit of an Alan identity, whom main cultural features would probably, as Romano-Germans IOTL, be made up after their entry in Romania to get more distinct from provincial peoples they were close (culturally speaking).
I'd stress this : they would be pretty much undistinguishable, wherever they settle, from the Romano-Germans that would have taken the same place IOTL.