That could definitely work for a cycle or two.
Not familiar with that system, can’t comment.
If you’re going to hit your squat hard, I’d try and keep your deadlift fairly minimal in terms of volume. I like the Kroc Deadlift Program on this site as a very simple, submaximal plug and go program that seems to fit well into 531 for me. Would you like me to knock together something that makes sense to me or wait for the big strong people?