@Stax we were planning on building the bottom of the cabinet ~4 inches above the top of the baseboard with feet instead of having the bottom enclosed and leaving ~3 inches between the back wall and the back of the cabinet with shelves offset from the wall to allow heat to escape - any other suggestions or do you still think that would be a bad idea?

A different plumber checked out our neighbor’s gas heat boiler while we were there with the neighbor. The flame was VERY loud, and I questioned the noise. Plumber claimed that the loud sound was normal. I have new photos that were taken by someone else at an opportune moment, so I don’t have a photo of the brand name (forgive me for not looking) or a photo of the flame and it’s location. I am thinking at this point that the sound we’re hearing beneath her utility room is the flame. The new photo shows more of the furnace, maybe able to see the valves that weren't visible in the previous photos. Would the seemingly industrial State brand hot water tank make noise? Please help me to figure this out! Thank you!

I find the current arrangement of dense shelves around the TV sort of overwhelming, which would only be made moreso by expanding them both vertically and horizontally. Do you need all that storage/display? I think I'd prefer a long console under the TV and then maybe a single storage piece in the corner or elsewhere in the room. You could have some art instead of all that visual clutter.

Found a place online that sells the subfloor panels with grooves to hold the pex line. I'm familiar with electric floor heat, and it looks like the pex lines are a lot farther apart. In a small bathroom, there might only be room for two rows of pex tubing, so I wonder if that will provide sufficient heat. i know baseboards don't provide much of a hot water line, but they have all the fins to absorb and radiate heat. Also not sure if the existing system could be easily converted by essentially reconnecting the water lines from the baseboard to the new pex lines or if other components are necessary. We would definitely have a qualified HVAC person do the conversion, just wondering how complicated it is.