I seem to remember the Dolphins having an interest in Emil Igwenagu when he came out (under Jeffy, obviously, so take it with a grain of salt). He's a similar body type to Clay, a FB/TE hybrid. He spent the last two years with Philly and was just cut by them, so he has familiarity with the system (and with Lazor, obviously).
Hoskins is another guy in the same mold and obviously picked a pretty good time to make a big play in a preseason game. Brackett is just sort of meh. The league is full of tight ends just like him. Then again Lynch going out means we're down to exactly one tight end who can even kinda block, and that's Sims. At the end of the day, though, those guys aren't as tough to find, though they're getting tougher. More and more of them are getting moved to OT in college.