A number of things to consider.
1) Stove ratings are given for a space with 8' ceilings, so in your case, with 13' ceilings you should be looking at stoves with a +-1800 sq. ft. rating. Remember, they heat CUBIC space.
2) In a shop/garage, I would recommend elevating the stove 24" on a built-up non combustible platform, in case some combustible gas/chemical fumes get loose. They are heavier than air, so they will hug the floor. This is actually code in CA for gas water heaters. A side bonus is that you don't have to get on your hands and knees to feed it or remove ash.
3) I don't necessarily recommend relying on a fan assisted stove, especially if you utilize those ceiling fans.
4) I never sold pellet stoves because where I lived the power was too unpredictable in the winter. As you know, they require electricity to operate. And yes, I know that you can use a battery or generator back-up, and that's fine for those that like that technology. I don't dispute the heat they deliver. With your free source of wood I don't think a pellet stove is a viable option.
5) As you have seen, talking about brands of stoves is like asking about brands of oil. Everybody is going to have an opinion, but the truth is, there is no BEST stove. It's what works for YOU; burn time, log length, looks, ability to remove ash easily, chimney size (6" is far cheaper than 8"), etc.
6) That's a beautiful installation of your Lopi Fireplace Xtrordenair. I installed a lot of those and they are great heaters.
7) The reason your chimney quote was so high is because from the interior, through the block wall and up the outside to the termination, it has to be Class 'A' chimney, which will keep the exhaust warm enough to draft, and meet National Code (remember your homeowner's insurance). My only suggestion is to breach the wall as high as possible (12-18" below the ceiling) so that you can use less Class 'A' and more interior pipe.
I sold Blazeking as well. Good quality stove and long burn times. Catalytic converters aren't super sensitive to wood, other than plywood, but if you're going to burn 'trash' I wouldn't recommend stoves that use that technology. Typically, stoves with converters burn longer than those without. The replacement cost of a converter is going to vary with the brand but approximately $150-$250 when I had my store.
Good luck with your research...