Wetroom Guidance Please - Tile Advice

[Mongo]

Afternoon all,

I'm new to these parts and new to projects in general.

We have a disability wetroom with a blue vinyl floor.

I have now stripped the entire room out to bare floors/walls.

This included a metal shower former with an impey gully surrounded by 12mm of plywood on standard floorboards.

I'm looking to replace this with a tiled floor but looking for some guidance.

I was hoping to replace the ply with a 6mm ply, tank it with aquaseal tanking solution, then place aquadry waterproof boarding on top.

1. Should I be able to replace the gully for a tile specific one without too many issues?

2. How do I tank the former?

3. Should I be able to tile over a metal former?

4. Will the ply/boarding combo provide me with enough protection from water whilst making sure the tiles aren't going to move and crack the grout later?

I already have the existing former and the aquaseal, the rest is under research/debate currently.

Thanks guys.

 

[One Day]

Honest suggestion here- rip it all out and throw it away. Look at a proper 'system' approach from the likes of wedi or schluter. In my experience (and i replace a lot of very wet rooms) anywhere ply meets tanking liquids coupled with inexperience, problems soon follow...
Sorry i know that's not what you want to hear but ultimately it's sound advice.