Seems like it's official that IWTV S3 "The Vampire Lestat" is going to be 7 episodes
According to AMC International sales website, S3 is still listed under IWTV umbrella and it's going to be 7 episodes.
I have been suspecting it for a while. The production time has been rather short (just over 4 months with all the breaks in between for conventions and whatnot) and we never heard anything about a potential episode 8, while having a bit of info about episode 7.
I'm pretty confident that S4 renewal is a done deal, so I'm not too worried. Rolin Jones have been hinting that they won't adapt the whole book this season. My prediction is that the ending of the novel is going to be covered this season anyway, while leaving a chunk of flashback material for S4. Then, S4 would be a mix of Queen of the Damned storyline with some unfinished business from TVL.
Timing wise, I'm still betting on the season premiering June 7th, with the season finale airing just before the SDCC weekend.