1 - Only your host can tell you what you currently have with regards to CPU and RAM. Those do seem a little low, but then again I've never bothered with shared/cloud hosting.
2/3 - That's who I currently use and never had a problem.
4 - No idea, so I'll refrain from answering as I don't want to provide mis-information. I would imagine it wouldn't be too hard.
6 - I wouldn't say it's less secure or more secure, just that there is always a chance of risk. I would be saying the same thing if you were on a VPS or dedicated server.