The AutoZone here has told me specifically that they accept oil AND transmission fluid. I wouldn't expect that they would have any problem with gear oil, given the similarity to motor oil. I don't think they'd allow brake fluid, but if I were to ACCIDENTALLY mix a ***little*** in with the oil, I can't see it hurting anything. Most of that used oil is burned, anyway.
I actually called the Detroit Water and Sewerage Dept. about the antifreeze question. I was told that it was acceptable to pour it into a sink drain provided that I flushed it with a generous amount of water to dilute it. I would obviously never pour it down the sewer drain, but if I spill a little on the driveway, I don't typically worry about it. The only way to recycle that stuff around here is to take it to an oil change place or mechanic, as the city and county DON'T take antifreeze. I don't feel right doing that, though, because I do all my own work. The last time the car saw a shop was for a recall last year. I don't remember the time before that.