I just want to clarify that this is the slab floor you're talking about and not something you are adding to a raised foundation? If that is right then it is a cheap solution and may be fun to do. Adding a laminate wood or carpet later is possible but in the case of wood laminate could result in the big chubby extra trim around the base moulding which a floor done by a good floor guy in the original buildout won't have to add.

Do you want to keep the wood floor? It is rare to see wood floors as garage floors. I've seen homes like this moved onto pour basement slabs (same concept as pile foundation...but with a basement instead of dirt. If you want to keep the wood, then there has to be a way to keep the wood off of the concrete. An 18" crawl space (dirt covered with 6mil poly sheeting or cement) is always an option. The 18" crawl space would have to be cross vented/heated properly. This is for "keeping" the wood. Flooring. I'm not sure what has to be done to remove the wood floor and have the building sit (joists and all) on concrete. Remove the joists and you have plenty of stability problems. You would need to speak with a local architect/building engineer who has some knowledge of what you are trying to do, soil conditions, etc. to get this right. In theory it can be done (we've just landed a small car on a comet...we should be able to put an old building on a cement slab)...I'm wondering about the expense to get it there (excavation + soil stabilization + concrete + piles, etc).

I like the idea of concrete pavers. What did you end up doing?

The freestanding bath fillers are vulnerable to being knocked. When you think about the physics of it, it is asking a lot of a small fixture to resist that amount of leverage. Talk to your architect. They should be able to come up with a support that fits with your design and is a bit more robust than the long and thin proprietary bath fillers. Also how far is your bath from the wall? If it is closer than 300mm I would still be waterproofing the wall, and with young children around I would waterproof it even if further away.