If your source code is on their server then, yes.
If only your ex4 file is on their server then, no, but they can use your EA if it isn't protected.
If your vps is encrypted, not without a lot of time/effort/work to get to it.
Depends on the type of vps used.
It does not apply to all vps servers.
Upon installation of the operating system the virtual drive can be encrypted.
Not really just do a bit of research and compare the specifications.
It's up to you.