I am also a comeback player starting this year after about 40 years away. I have been working on my embouchure and my breathing with mixed results all year. I think the advice and feedback you have already gotten is great, but I wanted to tell you about a couple of websites/resources that I am excited about and that address these issues very well. I can't remember if I heard about them here or on TH.
Anyway, the first one is George Rawlins website, grawlin.com. George has the knack of breaking down breathing and embouchure to its most basic components which has been especially helpful to me in starting over. He offers Skype lessons and consultations. His DVD is very reasonably priced. In fact, if you have a consultation, he will give you one included in the price. He is also a great guy. I had a consultation two weeks ago and after doing his beginning exercises, I am starting to see the results. Very encouraging.
The second website is Greg Spence's website called mystery to mastery. I haven't ordered these materials yet, but the sample videos on the website are great and I plan to order them soon. I love the approach of learning to break bad habits away from the horn so as to reprogram yourself.
Hope you find this helpful and good luck.