This isn’t new, there were Chinese mercs fighting in the first couple of years of the war.

https://www.newsweek.com/chinese-mercenaries-russia-ukraine-war-1876765

There was also that video doing the rounds of a Chinese merc asking his government to pull him off the front line.

Why would either need to side with Russia? They only have 140m people, a untrustworthy and soon to be unstable government. If you’re aim is to carve up territory then you don’t give a potential long term adversary access to half a billion people.

What weapons do they use to shoot them down? Guns? Missiles?

Probably so people don’t take the piss with the legal fees if they’re confident of winning. See the Colette Rooney vs Rebecca Vardey case for example.

We have “Visit Rwanda” advertised at premier league matches so guessing it’s pretty safe. Not saying the plan isn’t abhorrent or anything

https://www.theguardian.com/travel/2006/dec/20/cruises.green

Not at all. This article is 17 years old and planes have only gotten more efficient whilst the same old cruise ships continue to so the seas.

Plus a more recent article

https://www.treehugger.com/what-is-greener-boat-vs-plane-emissions-5185547