You've got a "core install". I think Contabo offers VNC out of the box but tbh best to set it up yourself. Apart from VNC, I think Ubuntu now supports RDP, but dunno I still prefer VNC.
Either grab the PID (process ID) from the script when its running, or the best scenario would be to create your own launcher that launches bots. Can use the Java Process API that's in Java 9. Additionally you'll need a way for your launcher to communicate with bots - a Socket works great here, but there are other options. Add in a database and you're good to go
Depends. It's an experimental build that's shared to the public so everyone can test before pushing a "real release" to all. Most of the time it offers improvements or bug fixes so you should always give it a go, would help the developers if you spot any bugs.
If it's buggy though, you can always use the latest stable build.
As far as I know OSBot doesn't allow external libraries in scripts due to security concerns, unless you use the libraries source directly.
In short - won't be able to do it.
1. Bad proxy in general:
1.1. Must be a Sock5 proxy, not a HTTP
1.2 You're using a http port, not a proxy port (check virmach)
2. You didn't authenicate your IP for proxy use, or just made a typo somewhere
What HunterRS said should work, but best if you would just install a Desktop, say xfce and install VNC (works a remote connection in windows). Makes things crisp, easy and isolated