That is true that one of glute medius actions is internal rotation (medial rotation of thigh), but I think the TFL is predominant muscle responsible for internal rotation (correct me if I am wrong tho). In cases of patellofemoral pain, and anterior pelvic tilt one would want to avoid TFL activation as much as possible. So i wouldn’t focus on internal rotation workouts, plus it teaches the incorrect/faulty motor patterns in terms of caving your knee in and the tracking of your patella relative to the femur. I am going to avoid internal rotation movements unless someone shows me evidence of its effectiveness. 

When doing banded distractions while performing external rotations mostly by these 2 stretches:

1)  in a lunge position with the front leg externally rotated, trying variations in the position and trying to work my way to a pigeon pose ( I cant get the pigeon pose)

2)  or on my back with one leg crossed–>piriformis stretch

I definitely feel very stiff in my right hip capsule (the ligaments surrounding the hip joint) doing the 2 mobs mentioned above. Their is a discomfort feeling of stiffness and slight pain in in hip capsule.

But apparently ligaments can be stretched through a process called creep deformation. This is the same process why your muscles get lengthened by performing stretches for extended periods of time. Thats why Kelly always says spend atleast 2 minutes a piece on a muscle. Soft tissues are viscoelastic in that if they are subject to a stretch they will shorten back to their original length, however if they are stretched for an extended period of time you overcome the elastic properties of the tissue and you get some deformation. Most of the tissue length will return close to the original length after a certain period of time after you exposed it to the stretch, but some deformation (or permanent elongation) remains. 

Again, this is the same reason why people get rounded upper back and anterior pelvic tilt. They round their upper back throughout the day. The tissue gets permanently deformed into its new position. So only way to reverse that is to start stretching the tissue the opposite way numerous times a day and avoid rounding your back throughout the day. 

In terms of how/why rolling on a lacrosse ball or rumble roller, and massage helps in terms of fixing soft tissue length and tightness issues I dont know. I dont even know if it helps as I have not seen any evidence. However, if someone would post some evidence to show that it works that would be great. The bro science theory is that it removes adhesions by ungluing the fascia between your muscles. So  the compression and shear forces causes the fascia (connective tissue) to break apart. I havent seen any evidence for this idea. Connective tissue is very strong and I doubt that the rolling can break apart the fascia.