I think the video looks like a bit of an odd reflection at 1:08 (near the first injector). I don't see the head gasket from that angle, you'd have to go under the intake/exhaust to see that line. You can see the valve cover gasket, but I didn't see anything wrong with it.

I did just do a brake overhaul - replace the master cylinder, rebuilt all calipers, replaced all flex lines. The brakes seem to work good and no drop in fluid or leaks detected (but again, I haven't taken it on a road test yet, as I'm still not confident in the car). Per suggestion, I did pull the brake vacuum line off and stuck some cardboard down to see if there was any fluid (indicating a MC gasket leak). It was totally dry.

I'm getting a suggestion for either valve seals (which I think may be an easy job that I can do and probably needs it anyway), or the auto trans modulator (which I have no idea about and will need to research how/why this may cause this smoke and how to test and fix.