Yes KOH is fine and you can use LiOH - either one with a pH of 11 when all is mixed. Cellulose thickener is to regulate spread rate and thickness. Other materials such as silica have and can be used.
If you are familiar with Haist you will recognize this:
from the 55 pod MSDS
POTASSIUM HYDROXIDE 1-5 001310-58-3
LITHIUM HYDROXIDE MONOHYDRATE 1-5 001310-65-2
T-BUTYLHYDROQUINONE 1-5 001948-33-0
SODIUM SULFITE ANHYDROUS 1-5 007757-83-7
SODIUM THIOSULFATE PENTAHYDRATE 5-10 010102-17-7
I am up to my ears in what are essentially monobaths. But the above used alone, don't expect a good cleared negative. The receiver sheet construction, nucleating properties and absorption of dissolved silver appear to be important, and while there are many patents and descriptions of the receiver sheet, none are specific (or say they are) to 55.
Please someone out there must have some knowledge of the production and preparation of the older receiver paper, the stuff that needs coating. If you do, I would gladly compensate expenses as this part of our project is proving costly, time consuming, and tying up resources as we cast about.
The rest is straightforward. If the economics are right, and we follow through (after knowing receivers) I am quite sure we will have a high quality 4X5 and maybe 8X10 field processable negative system with some kind of positive as a remnant, at least. It can be made as complicated as we like, but this isn't actually very hard as long as we remember we are not trying to make 55.