Expect the remodeler to measure the alcove, check the drain location and size, and look at the existing valve. Many conversions replace the valve, because a modern pressure-balancing valve and a new shower drain usually go in together under the same plumbing permit.
In Carver, the plumbing permit and its inspection request form go to the Building Department on paper, and the plumber books the inspection, which happens on a Monday, Wednesday, or Friday. If wiring changes for a new fan or light, the electrician files separately with the wiring inspector.
Once the tub is out, the remodeler should show you the subfloor and wall framing before anything new goes in. Repairing damage then is far simpler than discovering it after tile is set.