Light: I fight with small flash lights for up close detail work, and clamp on lights with the twisty 100 watt equivalent neon blubs.
Knobs: I have a bunch of Kenmores and so far no stuck nobs. Just one machine with a cranky top tension. I guess I'd just use the Tri-Flow oil or a good penetrating oil with some gentle persuasion until it surrenders and frees up. I have a 3 # hammer I can threaten them with if needed.
ATF: Won't hurt blue paint or any other color either. Just don't leave the machine idling in gear ...... LOL
Tensions: I usually do take them apart, clean and adjust them, after I've done everything else and test run it. I have a Singer 328 I just finished most of it's cleaning and the tension disks are rusty. BUT ..... for some reason the tension is good. At some point I'll have to take it apart and clean and polish, or replace the disks, for for now, it ain't broke, so I ain't gonna fix it.
Smoke belching blue clone: I'll bet something is bent and binding. Smoke from the nose???????????? Is there a light in that area? If not that bent throat plate makes me want to think somethings bent and really binding up.