Hi - I can't answer your questions about type ratings (except to say that a normal airline will do it for you) but as for the other stuff, the "bare minimum" would be to be human, less than 65 years of age and have the required licence / medical.
Clearly though, there will be many other people who meet these requirements, so you'll need to do something else. It all depends - some airlines may insist you've done all your training at one flying school, others won't care. Some will need to recruit for a certain demographic e.g. people with enough hours for an early command or people with low hours who won't be ready for a few years. Different recruiters have different hot buttons too - some may like graduates, others not. Some may like people who've passed all tests first time, others may not care.
However, when you get to the interview, they will probably look for somebody who has a high degree of emotional maturity, who will fit in to the job without upsetting or irritating anybody, who appears that they may make a good commander one day and who most people would find pleasant company down route.