1) Yeah it would be very painful at all times, most likely.
2) About having your low back stressed out, it may be due to overactive erector spinae. That is, your erectors tighten up and are hypertonic to compensate for having a weak L2 segment. This is only an assumption, many people go on for years with back pain and never get a good diagnosis with proper treatment. If you want a good diagnosis you would need hands on work with someone who is very well informed, but people like that are rare.
3) You pretty much wanna hit everything around the hips first, prioritizing that, and then hit the t-spine. When addressing mobility you don't wanna hit "muscles" really. Just certain movements. It gets too complicated because the hip joint has a complex system of muscles that performs multiple tasks.
The most effective stretches I've used were taken from a guy named Kelly Starrett on Youtube. Look up Mobility Wod, and it will pop right up. Don't be offended that he's crossfit, he's got some decent stuff. I can't really give you the vids without it being a complete mess, because many of his vids have more than one topic, and he addresses some issues more than once(there are 300+ videos to boot). Just skim at the first 10-15, and he'll give you some of the basic ones for the hip.
Try these:
Hip flexor stretch w/anterior band distraction*
External rotation hip capsule stretch w/ lateral distraction
Internal rotation hip capsule stretch w/lateral distraction
Rectus Femoris stretch (split squat with foot elevated on bench/chair)
*Band distraction (by this i mean hook a band on something sturdy like a power rack, couch,etc. and load up your hip by using band tension) is optional, but really helps in the case of any impingement, and is more effective.
Yeah, make sure you do SMR/soft tissue work too(this is very important if you want healthy tissues), with a lacrosse ball(very cheap 3 for like $5), and a foam roller($20-30 after shipping usually).
Don't be afraid to hit a lot of these hard for more than 2min. if you have time/want to.
4) Yeah... dude keep doing the glute activation work, it definitely helps pre-workout. Activation stuff + stretching + soft tissue work may seem like a lot, but it helps in the long run. Just make sure you don't just "do" the stretches or soft tissue work. Do that based on how you feel, and how your joints feel.
5) Toes out opens up the hips and knees a lot, allowing you to shove the knees out and for greater depth when lacking range of motion. Toes forward will allow you to generate more torque, and more tension in the bottom position(assuming you shove your knees out here too), but is much harder to pull off because many lack proper joint range in the hips.
Think about it like this, when you squat toes out, you open up the hip naturally, because external rotation tends to follow the feet pointing out, however at the cost of the knee being unlocked medially. Many argue that you need to point your feet out because you when the femur is externally rotated, the knees move out, so the feet out will allow the "knees to track with the toes." Although this may be a good idea, if the hip ever loses external rotation, that means the knee will come with it as well. This internal rotation will cause the knee to twist in, causing misalignment in the femur/tibia, and then you can possibly tear an ACL or MCL.
When you squat feet straight, you can still externally rotate if you have proper hip range in both internal rotation and external rotation, but like I said, that is difficult for some. The plus here is that, even if you lose external rotation during the movement, your knee is locked, meaning you cannot "twist" it in, because it will only move back to neutral because of your foot position. This also creates more torque in the bottom position, which can be good or bad depending on how flexible you are. If you are very flexible you can take advantage and use a more powerful "bounce" out of the bottom using the soft tissues like the adductors, instead of bouncing off passive tissues. Many argue that "the knees do not track the toes" in this type of squat, but most people have excessive valgus(knee caving in) anyway. The knee is in a much more stable position when the knees come out anyway, we shouldn't have to worry about excessive varus(knees out) angle for most individuals.
Wide vs narrow stance depends on how much muscle capsule length(hip capsule) you have. Wide puts more stress on the capsule, which is not necessarily good or bad(really depends on individual's mobility).
A lot of people will argue, but both squats are fine imo, as long as the knee does not internally rotate. You should also watch out for arches of the foot collapsing during a toes out squat too, but that isn't as important as knee position
Sorry if this is long, lol. Let me know if there are questions you want answered or any mistakes in there, typing stuff all at once isn't my thing.
