We are in the planning phase of replacing carpet and some tile with wood flooring. We are in central Fl, the flooring will be installed on a concrete slab downstairs and OSB sub-flooring upstairs. We are keeping the tile in the kitchen and baths. The tile has a finished height of 3/8 inch. There are seven places where there will be a transition from the wood to the tile.

We are looking at engineered products because of the climate. We will probably opt for a floating rather than a glue-down installation. This is not a DIY.

I'm wondering if we should limit ourselves to 3/8 inch flooring to match the height of the tile. If not, how much difference is acceptable?

T moldings can be cheated a little.

Floating floors are rarely 3/8th inches when the necessary underpad is calculated into the mix.
T-moulds or some other transition will be necessary to allow for proper expansion tolerance where you meet up to the tiled areas.
Since you are hiring a pro for this install, leave it to him to fabricate, if necessary, the thresholds you will need.