Brady to Miami is very real.
I think Miami's preference is to stick with the 25 year old QB who looked very promising at times last season. Obviously the big question for Tua is can he avoid any more concussions. He had 3 last season anyway, probably 2 in one game. It's a major gamble hitching your long term future to a QB with a dire concussion history. From one standpoint I think it's a perfect fit to bring in Brady for 1 season while giving Tua a full year to recover from the head trauma. Financially it could work because if Brady really wants to play another season, he's not doing it for the money, and he would sign whatever contract that works for Miami.
There doesn't seem to be another opportunity elsewhere for Brady at this point. Maybe the Jets if Rodgers completely flakes out on that trade. If they lose out on Rodgers then the Jets are going to be very desperate for a quarterback and may roll out the red carpet for Brady.
Tampa Bay still doesn't have a quarterback so they would take Brady back in an instant. Brady likely would only agree to that if they let him handpick a new head coach and promised him a future stake in ownership.