Sorry to be the bearer of bad news, but HEMS is currently in a "bubble." As an example, you look at Philadelphia (where I'm from) and you'll see 6-7 helicopters all covering the same territory, based...
There are a lot of threads on this, so it's worth searching. The best place to find the specific requirements of the position is via the service's page, as they all lay out both their requirements and...
Generally speaking, yes. Getting a flight job is more complicated then just that, but if all other things were equal, the experience gained from a tertiary hospital will be considered more valuable...
Your intrepretation is correct, but it doesn't matter, as the rule is bipolar as hell. If you are "on call on the employer's premises" you are "working while "on call"", and need to be paid for those...