Thank you so much! I have had the window open and closed (open when warm and closed when it has been raining) since Friday. I hope I have not harmed anything by doing that. I closed the window, have the AC on, the exhaust fan running (which it has been the majority of the time), and I put a fan right outside the shower!

I think your plan is ok with exception to how you plan on grouting over the cracked tile. Grout needs a pretty good space to adhere, a hairline crack isn't going to take grout. I would be worried that crack will cause you a water leak. I know there are some experienced tile people who frequent this forum, so hopefully they'll chime in. I would also suggest you post the same response over on the bathroom's forum. There are some master tile guys over there. Anyway you can get a replacement tile that will match the existing tile? That would be the best solution, even if it's not an exact match. I think the crack in the tile needs to be fixed somehow before you can regrout anything.

I never thought to color the white grout white, but that's an intriguing idea. Maybe I should consider that for a long term solution. Is it safe for in the shower too? (The bathroom in question is a tub/shower combo, but at some point I hope to do my master bathroom shower in similar tile and grout.) The grout is much closer to the original white after I let it dry from some serious scrubbing over the weekend. There is a little discoloration near the toilet though, so I think I'll pick up some oxyclean and a mr. clean magic eraser and see what happens. Thanks!

We have stone pebbles and three coats of sealer/enhancer on both the stones and grout. I don't know the types because the contractor did it and we don't have the packages. we put on three coats to keep the stones looking wet and darker. But I do know that it isn't slippery at all. the stones are very agreeably bumpy underfoot. we've only been using this shower for about a month, but so far I am totally pleased with the choice.