"I'm a little wary of the HA paste and plates for life thing..."
Jaw surgery usually requires plates to stabilize the bones that were cut. Once the bone hills the plates won't bother you at all. I think plates should be your last concern.
I can't say about the HA paste. It seems very few surgeons use that in the USA. However, it seems HA paste does not give excellent results for cheek augmentation. Correct me if I am wrong, please.
People in this forum talk a lot about A&G as if they were gold-standard for orthognathic surgery. And it might be the case, I don't know.
However, it is curious to observe that very few people in this forum had surgery with him to confirm their reputation.
I know many people consulted with him but didn't go to surgery.
Keep in mind that there is a huge difference between treatment plan and final results.