1. Side hills are scary. But the mower I have has "power steering", which is really just disc brakes you can enable one side at a time. You can squeeze the uphill side and it's less scary than one that doesn't have this feature. I wouldn't do 45 degrees though. But, if you are willing to go back and forth across the steeper stuff, then I'd say it'll work fine. When it was dry enough last Summer I ran the thing right across my little creek crossing and it's a pretty good dip.
2. I've run an older model with less HP that didn't have the squeezy hand brakes for steering. It was way more work to run. From a power perspective, using my current machine, if you can push it over, it'll mow it. They make a heavy duty blade for the thing and I recommend it. I've cut heavy stuff with both and the momentum of the heavy duty blade is awesome. It's also sharp on both sides of the blade so you can flip it over and have a fresh edge without getting out the file.
Edited to add - Wear ear plugs or muffs, and heavy duty gloves, eye protection.