Depending on evidence available at the time, the first search warrant may have been very limited in scope, i.e., electronic communications devices. New evidence/probable cause may have allowed for an expanded scope in a subsequent warrant.
Well, I don’t know what they’re doing - I don’t know enough about this stuff.
But the girl’s family has said that they are 100% confident in the work of the FBI.
I think their opinion is the one that matters - and they certainly know a lot more than anyone here does.