Things are looking good! Very neat and clean job too
And since you are so neat and clean, I’d say timing of removing the clips probably won’t matter. And I would recommend giving it at least 8 hours before walking on it. And same when to start grouting fresh tile
Only reason I recommend knocking out clips next morning is because the thinset isn’t super hard and is easier to clean the joints.
As far as the tight tile….With a smaller floor like that and being porcelain, I personally wouldn’t worry too much about it. Try to scrap out what ever thinset is beside it. Cutting the tile would be a pain and probably end up compromising your waterproofing
Marble and large floors are where that is a bigger concern