Question about wall application

Bear with me, folks, I have a silly one to ask.

First let me say this house is not anything we're
overly concerned about with regard to reselling it
one day. It's home for us, but the land is likely worth
more than the house itself, LOL.

With that in mind, I'm considering doing a large scale
mosaic on the bathroom walls, but have several questions.

I am considering mesh application so that I can work
at my desk, then transfer the mesh with tiles to the wall.

Questions:

1.) Should I be picky about the mesh type?

2.) Advice for wall prep. Should I put up concrete board, then
apply the mesh / tile pieces to the board?

3.) Suggested thinset / mastic / whatever you call it?

Many thanks to anyone who may be able to assist.

KM