I'm pretty much in agreement with xtrema. Over all your alignment at full draw is pretty good. I do think that the somewhat cramped space you have there is causing a couple problems.
Even though you have the target set up on something, your bow arm in the last video is definitely angled down. You are not maintaining the critical 90* angle between bow arm and spine. This is also making your string shoulder look a little too high and can cause bow arm instability.
It is hard to tell from the video but it looks like you have a pretty good "death" grip on the bow. The harder you try to hold it still (with muscles) the more it will move. Try a more relaxed bow hand and arm and let your arm bones support the bow weight. (If you're not -- just can't quite make it out in the video)
The collapse -- ah, the collapse. It is there in each shot and, of course, the hardest to overcome on your own or through the typed word. Many times what happens is you get to anchor, and start to think about relaxing your fingers for the release, the entire string side relaxes and you get the creep/collapse.
Sometimes this can be over come by changing what you are thinking about at the time. IF you are thinking about the fingers and string release, your mind ignores the rest of your string side and it will just naturally "give in" to the weight of the bow.
Try to change what you are thinking about (as xtrema said) to shoulder and/or elbow movement only. Try thinking about moving them toward your back and perpendicular to the arrow line. This is one way to accomplish the "J" motion you want at release. Making that movement (it is very small)will rotate your forearm and consequently the fingers will "pull through" the string with no direct thought on your part.
That is one suggestion. Another way to think about or try it is to simply make the decision to move to your follow through position. No thought about the fingers, just move to the position you see as your final position.
Bottom line is that at full draw, you need to find a way to continue the shoulder/elbow movement back and to not ever stop that movement.
The anchor/holding position is not a stopping point!! Your string & string hand comes to a stop on your face but the movement on your elbow/shoulder cannot stop, they must continue to "press" to the rear.
Jon, I know this makes is sound bad and I don't mean for it to sound that way. You are REALLY very close to great form, what I have listed are what I would term small corrections that can produce BIG results.
Arne