My user is controlling a mech, and for immersiveness, instead of overlaid UI elements, there are screens inside the mechs. How do I get these screens to show health, points, etc?
I think the best thing to do (that is supported out of the box), is create a UI canvas and set the render mode to world space. This allows you to move it around, attach it to your mech, etc. You will just have to scale it appropriately.