I was on the run before so I couldn't respond to all your questions.
Picking up a mooring ball is pretty easy. The difference on the cat is that you'll have a bridle. You can grab the mooring lines, secure one bow cleat then play with the bridle.
Once you're on the water I don't think you'll notice the size, or that it will feel overwhelming to you. The twin engines make maneuvering pretty easy. You can turn the boat 360 using just the engines. Just take it slow, get a feel for the boat once you're in open water, then once in the mooring field you'll know how it responds.
There's a ton of room on them, you can set your drink, or plate down without worrying about it sliding off the table. The crew has a lot of area to spread out and relax
You're not going to get the thrill of heeling over but they sail nicely. Tacking angles are larger. But for comfort you can't beat them. The safety issue, regarding kids wandering around at night could be discussed...and precautions taken..like life jackets, at all times.
As far as reboarding though, I think the cat is pretty easy to reboard at the stern.