A peek is one thing, but from your videos it looks like you're staring at the mirror pretty much the entire time. I actually find the videos on the squat grip even more helpful than the book, because you can see coaches actually correcting real live people. Worth a look!
What are your rest periods like between your sets? If you can go 5,4,3 or something like that, a couple more minutes of rest in between sets might help you grind out those last couple of reps. A bit of wiggling around is pretty common as long you can overcome it without your form totally falling apart, like your knees totally caving in or something. You seem to do a good job of keeping your knees out though, so I bet you could grind them out if you fix that bar position and get better at staying in your hips.
I left the pain issue alone because I'm not a coach and don't have much experience with which form issues might manifest as pain where. Can you be more specific about where it hurts? Coaches frequent this forum so if you can describe it I'm sure they could be of more assistance.
As for your deadlift, that sounds like about par for the course! Of course your back wants to round or slip! It's pulling a heavy ass barbell! Without video we can't say for sure, but it could very easily be that the "pressure" is just your back working to maintain the proper position. Do you have video of it? If you're worried about your back, just add a belt. I really don't think it's going to hurt your progress. It actually helps the core muscles contract harder, so all the talk about a belt leading to a weak core seems like unnecessary concern.
I just went through your log a bit, and I don't see any workouts where you missed reps. Looks like it's pretty much successful 5s across, except for a 5,5,0 at 155. The biggest red flag I see is that you've only gained 10 lbs in two months. That's not horrible or anything, but this early in LP you could probably stand to be a bit more aggressive with the weight gain, as much of a challenge as that may be for you. I made that mistake myself, and had to try to play catch up later in LP.
Have you read this?
The First Three Questions | Mark Rippetoe
I've never seen a coach in person, but I hear they can work magic in a single session. I'm sure it's worth a visit, even if it's only a one time thing!