About the only reasonable way to stop a bear is an electric wire. That electricity is very high voltage but a pulsing low amperage blast. It will not injure anything unless it gets tangled in the wire and can’t get away. Practically anything that touches it once learns not to try again but new predators re being born all the time so you have to be consistent with it.
I’m going to go against the grain here. I like being able to walk inside my coop to gather eggs. That way I check on the flock and see if I need to do any cleaning or repairs. I’ve found snakes, a possum, and a dead chicken inside the coop. I fully agree, make sure you have enough headroom to walk in there.
I don’t have any great advice on handling a rooster. Some people cuddle it every day from the time it’s a chick. Some of these go human aggressive, some don’t. Some people totally ignore the roosters and let a broody hen raise them with practically no human interaction. Some of these go human aggressive, some don’t.
I don’t put too much faith in a rooster protecting the flock. Some will fight some predators, even sacrificing their lives to protect the flock, but most I’ve seen are just as likely to lead their flock to safety as get between the flock and a threat. A good one will investigate things but some are better than others. The big advantage of a dominant rooster as far as security goes is that that act as a warning system. A good one is always on watch for a threat, but again not all are good. In the absence of a rooster, the dominant hen will often assume many of his tasks, including watching for danger.
The only reason you need a rooster is if you want fertile eggs. Anything else is pure personal preference.
From your sketch I’m not sure if you are planning on a solid bottom to the run or not? To guard against digging predators I suggest you use an apron. Lay about 18” of wire horizontal around the outside of our coop and run and attach that to the bottom of the fencing or coop. You don’t have to bury it, just weight it down with something until the grass can grow up into it and hold it down, but taking the sod up, putting the apron down, and replacing the sod generally isn’t too much work and keeps it out of the way of lawn mowers and weed eaters. The idea is that the digging predator goes up to the fence, starts digging, hits the wire, and does not know to back up.
Overall a very good plan. I have comments though. Most building materials come in 4’ or 8’ lengths. If you plan around those dimensions you can often build a larger coop with less cutting and waste and not much more money. A 6x8 can become an 8x8 with one additional piece of plywood, though your roofing costs will also go up. You’ll have to use longer rafters to span the 8’ versus 6’ roof and get an overhang, but check how much area you can cover in a bundle of shingles. Just something to consider.
I also suggest sloping the roof of the coop and the run to direct water away from the run or use gutters to divert that water. The way you have it now, half the water that hits the coop roof will run down onto the run cover and leak through into the run if it doesn’t go all the way across and into the run. A flat roof is not good. It needs to slope enough to carry water away, otherwise it leaks through. Remember to make the roof strong enough for snow load too.
Chickens usually don’t mind the cold but they hate a cold wind blowing on them. They generally don’t like snow a lot either, at least for the first few days they see it. You might consider creating a protected pocket on the upwind side to block wind and keep some blowing snow out. I’ve got a solid gate on my run which is right next to the coop. Often when a wind is blowing form that general direction they will be outside huddled in that protected pocket.
You might read this. The best time to fix a muddy run is before you build it.
Pat’s Big Ol' Mud Page (fixing muddy runs):
https://www.backyardchickens.com/web/viewblog.php?id=1642-fix-a-muddy-run
The idea is to stop water from going in there to start with and let any that gets in drain out. In addition to gutters and sloping roofs, consider where you position the run and coop to start with and maybe use berms or swales to keep rainwater from washing in. Your run needs to be high enough so any water that gets in has somewhere to go. If you can’t handle that by where you put it, you can put something solid (but allow drainage) around the bottom of the run and add a few inches of sand. Sand works great in allowing the water to drain out but the water needs somewhere to drain to.
A great place to put ventilation is under any overhang of your roof. It’s over their heads and the overhang keeps rainwater out.
I don’t know how hot it gets there in the summer, but heat kills more chickens that cold. In the summer you need ventilation down low as well as high. Hot air rises. If you have openings high and low you can more a lot of air. In warm weather a nice breeze hitting them helps. It’s when it’s real cold that a draft hitting them is a problem. So fix low ventilation so you can block it off in the winter.
It is a nice plan but start building as soon as you can. They grow up awfully fast.
Good luck!