I think Cruz will do well with Evangelicals in Florida. Not with blacks, but then I doubt many Florida blacks will vote for Trump over Hillary, either. Much of Trump’s argument to blacks is directed to black workers who want tariffs to protect their jobs. Florida really doesn’t have much of a manufacturing industry, so I don’t think that’s going to make much difference in Florida. The other part of it is immigration, but immigration is a two-edged sword in Florida.
It didn't happen in the primary (at least not sufficiently to beat Trump), so why would it happen in the general election (sufficiently to beat Hillary)?