I know where you're coming from with your bench and deadlift, but if you feel interested in powerlifting my advice is just try it, you should know right away/afterwards if you'll want to keep doing it. I don't know how high your other two lifts are but with a 500 squat I would imagine your bench and deadlift can't be to bad either.
As for making money from powerlifting, I think the top guys like Kroc and Tate do make good money, but that's probably because they also have a business/entrepeneur side. I would advise against competing in powerlifting just for money, from what I've gathered the top, highest level, elite guys only make $10,000-$15,000 a year after taxes from competition money, many of them own their own gyms as well so they can add to their income that way too. Sponsorships may bring some more money, but I'm not to sure. I hate to say anything that would persuade someone away from powerlifting, but I imagine football would benefit you more if you want to make money from your athletic ability, you probably know that already.
I think becoming a certified trainer would be a very good idea, it's something I've also gave considerable thought & interest to myself.
I currently use 5/3/1 and I highly recommend it, but I used to pyramid up to a new pr every workout, which worked for me in high school when I first started lifting, but after the beginner gains I simply plateued.