My guess is the N. Korean masters want to get their troops some combat experience. They figure their troops will do well or get chopped up - either way it will be a valuable experiment for the army and, maybe, ingratiate themselves with the Russians.
This looks like PR.
They won’t speak Russian. They will require their own food types. No value in them being there.
Nah, I would guess this means 20 guys will show up to build some small housing structures in Donetsk. Using tools and materials they are familiar with.
They will be chewed up. Russia was considered to be number 3 in the world and have been decimated with over 500k dead and all their top armor gone. Don’t believe me? Take a look at the May Day parade where only 1 WWII T-34 was present.