Carbon Printing - Sizing Art Paper 

Correct. No sugar or glycerine.

Yes, that should work fine. Here in the US We typically get a 37% stock solution fo formaldehyde. I mix that down to 3% solution of water and the stock solution and it works just fine.

I know people who have printed straight to Yupo. It apparently needs a good cleaning before it is suitable to print. I like art paper for it's aesthetic qualities. However, it is difficult but rewarding. The bubble you experienced are almost certainly the result of inconsistent sizing. I've gone through that before. Once you have good sizing, blisters will stop.

Yes, that should work. Carbon can be printed to a wide variety of surfaces.

Yes, brushing may require two coats as it will be thinner than a rod coating. Only experience can tell.

It's just 5% gelatin solution with about 25 ml of isopropyl mixed with 25 ml of water per liter to help eliminate bubbles. After, shooting this video I started dichromate and hardening in the sun instead of formalin for hardening. I like this method much more. All the details are in the book I co-authored with Sandy King. retrogradestudios.net/carbonbook

the 22x30 140lb extra white hot press It's a little less expensive than Arches. I used to use Arches, but got burned one too many times by inconsistent sizing that can leave light spots in a print, particularly when a print is lightly sized. Whether is is considered cheap of not, the paper performs very well. It's consistent between batches. That said I've switched to Hahnemuhle platinum rag. I like the surface more. It's a bit smoother, but the real feature is the sizing. It dries flat, very flat. Better than any watercolor paper I have ever used. As an added benefit, you can use one stock of paper for carbon and hand coated processes like pd/pt.