Blueshear

Leave a depth of 5mm or slightly more if you are going for vinyl

If you like Terrazzo, maybe you want to consider installing as a whole piece that are cast insitu, meaning no joints like tiles. I have seen it in Malaysia and it look very classy.

Maybe you can try a seamless cement raw look for such small toilet, instead of using tiles. Will make it look much bigger.

Greglhc, I have a screed wall in my home and it very cooling to touch. it definitely heat trapped from hours of afternoon sun and it also depends what type of screed materials one is using

Don't need permit unless it involved hacking.

It depends on whether it interior or exterior, if the cement finish is in the interior, it would not transmit heat from external to internal and in-fact it would be cool to touch.

Try visiting this link to contact the specialist who is doing this type of work www.designerfinish.com.sg

You did not need to hack the wall tiles in order to do a cement wall and to do a cement screed floor on your existing floor, I don't think it would be advisable as it will reduce your floor to ceiling height. Another way if you prefer to do a cement finish look is to top up a very thin layer of cementitious finish. A specialist contractor have more skill set to do all these than and ID.

Yes, you can use bright colours for minimalist concept as long as your fittings and furniture are not cluttered. Right choice of flooring material is the crux of minimalist design in my opinion.