The problem I see is your alignment.
Stance should not matter if you are properly aligned. That's why I preach proper alignment so hard, and its all from the waist up. If you are properly aligned, it really shouldn't matter if your front foot is forward or back as again, its all controled from the waist up. You can carry your alignement with you whether you shoot up hill, down hill, rotate left or right, bend at the waist forward or even reverse cant.
Being properly aligned IMO is PARAMOUNT for the bowhunter who doesn't always get that back yard stance, and has to creat and manufacture shots in the field. No telling where your feet will be, and sometimes you might not even be on your feet.
If you look at your 1st pic, you will see if you 'carried out' the shoulder line, it would be pointing too far to the right. Its pointing too much directly toward the target than just perpendicular. You have 'closed' your shoulder alignment. This closed shoulder will make your draw length longer than is should be.
If you start with your feet paralell and perpendicular to the target, this will naturally get your shouldlers perpendicular...so yes, when learning, get your stance right so your shoulders are right. Once you learn to address the target and gain confidence with your ideal 'back yard' shot, then you can push yourself to learn to shoot from other positions by controling that aligment from the waist up, and everything below the waist really wont matter.
The elbow bend is purely personal. Mine is locked solid, and I like it that way, but I have a natural bend in my arm as well and it wont staighten out all the way like some. Other's like a bent elbow, so find out which one works best for you.
My draw length is 27.5 to 28 depening on the bow, so I aint much help on the long arrow issue.
Best of luck to ya young man.