Guys take into consideration that not all of them are candidates to manage justbarcelona. I can see Cesc as manager for Arsenal maybe one day and Puyol/Busquets/Iniesta as managers for Spain. Abidal could manage some french club one day as well. Who knows, maybe there could be a twist and one of these guys could be manager of a newly independant Catalan NT. Hell maybe even Pique could be managing one of Shaqira's tours one day
Puyol is either going to be an amazing or horrible manager, passionate field generals like Carles have a very high failure rate.
Xavi is the logical choice, he's a football nerd to his core and probably reads zonal marking. I could see less obsessed players tuning him out though, Emery style.
The next great Barca player to be a coach is gonna be Rafa Marquez anyway.