Flooring upgrade from ceramic?

You can install a laminate hardwood floor over the existing ceramic tiles without ruining it in case you or someone else wants to change back in the future. A laminate floor would not be attached to the ceramic since it is free-floating on a cushion of thin foam backing. Another possibility is Allure which is a Home Depot product that is available in many styles and it can be used in a damp environment. Sheet vinyl or linoleum would distort over the grout lines of your existing floors so they wouldn't be a good option. Good luck on your choice.

You could lay hardwood strip loose over tile on top of an underlay.

If it was me I would use latex levelling screed to fill all the joints and then use a really good wood effect vinyl (eg Amtico) - much better value than timber and less liable to damage from the pool..

You could always go with linoleum or the vinyl tile stuff. For a floor that will be exposed to water the ceramic tiles or stone tiles are probably the best.

I'm with the Amtico suggestion -it is virtually indestructable, unlike any real wood floor or cheaper laminate, and the wood-effect Amtico's are 100% realistic, so the only way to tell the difference after a few years will be that the wood will be scratched, chipped and probably stained. The Amtico won't.

Just lay it on top. You may have to remove any shoe molding around the baseboards.

Just put down some kind of under layer.