RB's are so cheap that it doesn't make sense to pass on practically any upgrades in FA. Crowell, Hyde, Hill, and Anderson is a solid group. Maybe I'll be wrong, and a couple will get surprising contracts, but at least one or two of the four should be very cheap. Every one of these RB's suffered from poor QB and poor OL play in 2017, and each is a physical and would serve as a good compliment to Drake.
Potential hurdles: what type of role are they looking for? vs what role is Miami willing to promise? Miami also needs at least one or two more RB's who excel in the passing game, and these players range from not-good to OK receivers. But, Miami still needs a physical RB to get tough yards inside, so there should be room. Otherwise, you're looking for guys like Chubb or Freeman to fall.