elves from allerian stronghold had a problem with blood elves loyal to kael and whenever they speak they do so in reference to them!One last time, we have absolutely zero evidence that Allerian elves have any bad relations towards Alleria because of that Sunwell accident... it's purely assumption on your part, not backed up by any canon information from the game, so stop taking it as granted. It's not. It's just a theory at best, and not really convincing theory.
Another thing is, that while elves of Allerian stronghold expressed homesickness, they also expressed that they are not going back home because of the direction Silvermoon government has taken. That should be enough for you to consider their loyalities.
You should also think about horde aligned High Elves. Once high elf decide to go red team, he will be most likely asked to take on identity of a blood elf, since it's pretty important for sin'dorei society, and being high elf means being oblivious to hardship they had to endure in order to survive. Being called high elf is not a good thing among sin'dorei. You should know that...
Also, Auric was seen in Quel'thalas ONLY during Quel'dalar questline. He is not been shown here any later. He was not here during Cataclysm, not even during MoP, not at any time later. We've seen Alleria's visit to Sunwell, and guess what, Auric was not present. He is in fact not citizen of Silvermoon. What's worth mentioning, while things get bad during that quest and Quel'delar rejects Lor'themar, Rommanth instantly accuses Auric from treachery, showing us what does they think about him. He is merely allowed at Sunwell, they are not being friendly towards him.
You have been also shown numerous sources from devs of the game stating they are not going to change status of existing NPCs or doing brand new NPCs. All you they'll do is to add new customizations to "no name" NPCs which wanders the cities, like town guards, etc.