I haven't tried a "bachelor coop". Well we did do that, but they were still young and hadn't developed full hormones yet, so they weren't aggressive. One guy in Hawai'i said that a bachelor coop next door to the hens will work for juvenile roosters but not for full-fledged hormone-raging ones. He said if the adults could either see or HEAR the hens, they got aggressive with each other. He had enough space to place his bachelor coop far, far away from the hens and he said he had several full-adult roosters getting along fine.
Now that is just one account I have read about that, not having tried it myself. I don't know if that is more common knowledge than I am letting on. I suppose it also depends upon the roosters. We've had several roosters and some were just plain mean, even as youngsters. These ones went into the freezer first. Others are more gentle. Two of our roosters have attacked my wife, not hard, but hard enough she didn't want them to make a habit of it. So she gave them the "love treatment" in which she cuddled each of them for a good 5-10 minutes, held on to them firmly but kindly. They never attacked her again!
If you're not averse to butchering them if the bachelor pad doesn't work out, that's a good route to go. Re-homing them is often not that easy. Lots of folks end up with roosters they don't want, don't want to butcher and try to find them homes...and so is everyone and their brother. If you put out a classified of "Free rooster to good home", know that most of the time, whoever comes to get the rooster will be making room for the rooster in the home of their stomach!
This all brings up a good thing to think about...do you want your chickens to be pets or a source of food? We love our chickens, but made it quite clear to ourselves that they are not our pets. It makes it so much easier when we need to cull the flock for whatever reason.
Using the buckets as nest boxes sounds like a good idea! Since it can get hot (and humid?) in your parts, you might consider drilling some vent holes in the bucket for air circulation. If you can get lids with the buckets, cut the lid to about 1/3 it's original size and snap it on the bucket. It will help keep your bedding from getting kicked out every day. You could then unsnap the partial lid for easy cleaning of the nest "box".