Remixed the great tripod phone mount here https://www.thingiverse.com/thing:4297510 to fit directly onto my sony tripod

Doesn't Matter

Yes

0.1

Print at 0.1 with an 0.4mm nozzle to ensure the captured part can move. You'll want supports touching bed only in order to print the diagonal on the bottom.

I ran a knife down each of the seams to free things up then it moved beautifully.

Install an elastic band or two on the front to clamp the phone.