Haha, I've been diagnosed with carpal tunnel two separate times in the past and the pain I was experiencing is long gone. Good thing I am a procrastinator.
No matter what headphones I use my mix never sounds quite right when I listen back on speakers. I can get close with tone and separation but stereo imaging is always a fail for me. Effects always need adjustment as well.
I have a few different sources of noise that include heat, AC and dehumidifiers. I turn off whatever I think will cause an issue while recording and then turn back on when finished. Yeah, it's a pain but it's worth it. It's worse for the folks that have outside noise that they cannot control...
I have my music room in a basement and IMO you only need to sound proof the ceiling and whatever is above ground because no sound is going to penetrate concrete and dirt. Acoustic treatment is a science that I have no expertise with but I do know that eliminating standing waves is very important.
I know more people that care about lyrics than not. They want to hear a story or some sort of message. I personally would rather hear something meaningful than some BS lyrics but not a deal breaker unless the lyrics offend me.
For me it always starts off mono and many times I double it by recording another track with either the same guitar or sometimes a different one, then the tracks are panned right/left. I have recorded with two mic's but i almost always end up recording with either one LDC or one SDC aimed in...