could you post a pic

It small But your cabin sink unit is a good idea as you have storage space and it looks neat. I have changed my bath many times to shower unit and it has leaked every time, some times it has been the plumbers fault or bad design then it was a visitor who let the water spill while showering the last time it flooded the insurers wanted the bathroom TANKED! meaning waterproof walls and floors. This is done by an experienced plumber contractor of repute! as the insurers said too many claims from too many people with bad waterproofing. the insurer said they would not insure again or any other clients who had not got their bathroom water proofed by expert plumber fitters. SO I have gone back to the Bath with a shower enclosed and found it tops for waterproof.

We also bought our house before babies - but I can now tell you they usually are mainly in the tub yrs1-8 maybe even 10 or 11! We opted to put both a tub (with an electric shower) and a walk-in shower / wet room type arrangement in the main bathroom. Seems like a lot in 1 place but works for us.

You should probably think of the floor covering in the overall plan as a light colour or dark colour may have an impact on whether you choose a light or dark colour for the worktop. Two different worktops, one on the island and one on the rest of the units might look well too. I like timber for an island but only if you don't need the worktop to be heat resistant and it's not near the sink. We've picked a dark grey for our island and will probably choose an off white worktop with a vein in it to contrast with it. Good luck with your decisions!