Hmmm, still kind of too broad. I could write books on that subject, which would conflict w/ my day job.

You should go to the Lestat RPers. Some even have a page for headcanon stuff, like askthebratprince. Other Lestat RPers I’ve seen and enjoy watching (in no special order):

eternallyfabulousbratlestat, monsieur-le-rockstar, maestrolestat, gorgeous-fiend, princelestat, primusdux, asavagegardenindeed, lestattheonetruepope

I’ll try to share my own headcanon at some point, I’ll tag it as iwantmyiwtvheadcanon, so you can search that tag later. Really though, go for those RPers, they’ll satisfy you better than I can 😉