Yes to whitewashing!!! Also paint the doors and trim white, in my opinion the floor can stay if it is hardwood, or maybe painted dark charcoal white, polished concrete sounds great, too. And yes to pendants, maybe the bird cage ones that seem to be very popular. Reupholster sofas in a solid white or blue, put a large blue and white striped rug and white curtains.

You should have minimum 5 ft but 6 ft is ideal. I've played pool where tables are 4 ft from the wall and it is too close. The standard pool cue length is 57" and the draw length is about 6" so 5 to 6 ft would be ideal.

Personally I think you are better to wait until you can afford to put back an in ground pool as the one's that I have seen sitting above the ground look like an eye sore - a temp pool - that looks like it could collapse at any time. Maybe while you save for the bigger project you could rent / buy a large Spa Pool.

I do like the tiles... however I suggest you give a think about the future cleaning of the grouting before you commit. Near a spa, the moisture in the air is a breeding ground for algae and mould.