Uv glasses aren't really needed as uv is only really exposed when printing at whibh point the resin and build plate will cover the uv source plus the printer cover should be uv filtering.
Painting resin minis is the same as painting any other I've found other than they can be more brittle so you've got to be a little more gentle but it's not a big issue.
Yes. You can mix it into “normal” resin to give additional toughness to the parts. It helps with small features that might require more delicate handling normally. I’ve used it at like 20-30% for stuff that needs just a little give, all the way up to like 80% for stuff that needed to be fairly flexible.