Master bathroom remodel: layout before finishes
The common wins are the same in most Central Florida homes of a certain age: losing a large corner garden tub nobody has used in a decade and giving that footage to the shower, replacing a single vanity with a double, and separating the toilet. Whether fixtures can move depends on where the drains run in the slab, which is a real constraint rather than a preference.
Moving a drain in a slab
There is no basement here. Relocating a toilet or a shower drain means cutting and re-pouring concrete, inspected under the Florida Building Code, which is entirely doable and is a meaningful line in the estimate. Moving a sink is usually easy; moving a toilet is not. Knowing which you are asking for changes the number substantially.
The parts you will not see
Waterproofing, slope to the drain, and how the niche and the corners are detailed. On a primary bath those matter more than anywhere else in the house, because a slow leak here reaches a bedroom. See tile and waterproofing.