Exactly. OP can unscrew the fixture and will probably see hot black to fixture, white to white, and black coming back from the switch to the fixture. It's an easy fix. Hot black to switch-leg white, returning switch-leg black to brass screw on fixture, chrome screw on fixture to neutral.

The rough opening is almost certainy framed in 2x4. If you wall is 4.5" thick, for example. The safest option is to screw a 2.5" or 3" eye screw through the trim and deep into the rough frame underneath. Hang from the screw yourself to test it, then attach the jolly jumper with a carabiner to the loop below the clamp. My parents used a hook, not an eye screw and occaaional i could jump the spring off the hook. My kids had the over the trim clamp version until we moved to a house with no trim. It is the best baby product ever. I hope your kid enjoys it.

I've never gotten a straight answer on this question. Steel studs can rust, wood studs can rot. Pressure treated can rust your nails or screws if you're not careful. When I redid my basement, I found 40 year wood that was good as new, but I live in a high elevation cold/dry climate.

Epoxy floor would look nice. I said I would do it on my floor 10 years ago, but it hasn't happened yet. You can do treated wood for the bottom plate in each wall, the other option, u/strongmans mentioned it, is sill gasket, basically 3.5 inch wide closed-cell foam, about 1/8" thick that comes in a roll that you put between the bottom plate and the floor. It's also used between the top of the foundation and the sill plate (or anywhere wood touches concrete) in most newer houses.

If you're building just a few walls yourself, spend the extra money and use 2.5 or 3 inch deck screws instead of nails (Robertson #2 head if you can get them in New England?) Very useful when you mess up and need to redo stuff, and you can hold the board with one hand, the drill in the other while the drill bit holds the screw in place.

You can leave the floor as is, especially for a workshop, and leave the ceiling unfinished too. My basement is 70% fully finished (drywall ceiling, carpet) but I've left the laundry/utility room and a storage room with no ceiling and a concrete floor.

This is correct method. Foamboard directly on the concrete leaves no room for convection. In winter the top of the basement wall will be cold and the bottom buried part will be warmer. You do not want warm air moving and coming into contact with the cold and condensing the water out. In an unfinished basement this isn't a problem because enough heat is being lost through the wall that the dew point is somewhere in the wall, but once you insulate inside, the inside of the concrete will become colder.

u/strongmans suggestion to frame a proper 2x4 wall, not just use furring strips, is also a good one, because then you have a proper wall to hang stuff on in your shop and you have room for electrical boxes on the exterior walls.

I just meant any HVAC foil tape that has that has the removable backing. I've seen it at Cdn Tire and Rona. But beside it will be a cheaper tape without the removable backing that is basically metal coloured packing tape, avoid that. I don't think the brand really matters.

Pay the money for this tape, that has the consistency of aluminum foil and has the wax paper backing that you peel off. There is another cheaper tape that is more like metal coloured packing tape that doesn't stick as well and doesn't compress as well.