For belts, look for one that is 2" in front and 4" in back. There are cheap ones on Amazon to see if you like them, then buy a good one if you do. Conversely, these are the type of belts most commercial gyms have, Maybe get lucky and they will have one that fits.
Lower the weight like you would lower anything. Literally pick up a pillow and lower it to the ground. That is your natural path, do that with the barbell and see how it feels.
I'm "training" some co workers and one gal has never lifted in her life. She can pick up the bar well, but putting it down is so weird for her. I said don't think about it, just put it on the ground like a piece of laundry and now it is a little more natural.
Form from off the ground to lockout is spot on, even for a deficit pull where there is naturally more forward pull off the ground.
And feel free to post all questions. Powerlifting communities are very helpful, we leave the bros over at other forums