This is far from official people...
Just bc Pep displayed interest does not mean the deal is done and he is leaving. It's important to remember that at the end of that interview, he mentioned that no one leaves Barça unless they aren't playing enough. I think this is more him saying I'd love to have him if he wants to leave.
Again, Thiago seems to have not made his mind up yet. I think after watching Neymar destroy Spain and Xavi's poor showing, he might still fancy one more season here. Being able to play with Neymar has to be in the back of his mind and if Tito really plans on scaling back Xavi's time, it still makes more sense to stay here.
If Thiago wants to leave tho, he will go with Pep but I could easily see that move backfiring as well. That move will piss off the dressing room, as if to say only after a month of training and no competitive play, he thinks he needs Thiago. I'd be pissed if I was Mueller or Kroos.
Pep would be wise to be more conservative this first season tho. Trying to change too much would be ill-advised.