The draenei death knight combination is very shaky in lore, given that they are light zealots having your cousin walk in with a rotten face and worse smell would be abhorrent to them.
DK lore is also they’re fairly focused on combat, there’s some parts that (i dont know if they were retconned) established DKs having to inflict pain to survive - they’re all around pretty edgy overall and an odd sight to see in your local tavern enjoying an ale.
The reaction of ordinary people to a hulking undead monstrosity isn’t going to be favourable, not in the least due to the myriad of atrocities they’ve witnessed at the hands of the Scourge et al.
Rotgarde are forsaken loyalists, though I don’t think they accept undead elves other than as dark rangers.