Active job

Bathroom renovation

Wanting to know if we need to replace current gib or coat/paint over it. The floor and walls will need to be stripped ( everything taken out except the bath). Wanting underfloor heating but unsure if we need to put anything over it. I am wanting 2 shelves built into the wall . One above the bath and one in the shower. Will need a electrician as am wanting to move heating rack to the opposite wall. Will need Tiler to tile the floor and put a few strips of tiles onto walls. Have new shower and cabinets and toilet to go in and the cabinet will be wall hung. Am wanting to maybe get a drain strip or plug for shower but am unsure currently. Will need plumber for this. Have tiles ready also