I like every solution you listed Peredv
I happen to have some rather expensive high quality mirrors, they are .2 mm thick lapped and polished silicone glass, coated in aluminum and are first surface, So they could handle much more heat than our standard plastic mirros and they are optically flat, so better beam focus could be achieved.

If any one is going to give this a go let me know id love to chat with before you start, and send you whatever parts I have kicking around that would help your cause.
Another change I would make is to change the hole moving armature that the mirror and magnets and damper are mounted on from plastic to aluminum foil or titanium foil.