Hi,
May be a bit late to your questions, to my knowledge GT has one interview, which is by invitation. I believe those requests are being sent out on a rolling basis. As you may be aware from reading this forum, Laura usually does the interview but has recently had a death in her family so others are stepping up. I had my interview last week with Kayln, and it was completely behavioral. As for decisions, Kayln said it would be about an 8 week turnaround. Given they will be without Laura for a significant time during round 1, I would not be surprised if they are behind a bit in sending interview requests out.
Hope this helps!