Renting aircraft isn't a problem if the hirer and hiree have a specific contract in place (Casa will want to see it). You'll need financials covering profit and loss etc. Insurance requirements. Everything covered in 82.0 and via the manual. For the chief pilot approval it is anything from a few hrs to a couple of days depending on your experience, type of operation and how confident they are in your operation. There will be a thorough written, oral and flight test. If you do poorly they have the power to revoke your entire licence. So if your not up to standard you could walk in a chief pilot wannabe and walk out unlicenced.
After doing a lot of research and saving a lot of money I would probably advise finding a current Cp to mentor you. Only saying that because a serious candidate would already have knowledge of what's involved!