Before thinking about an AOC, I suggest you need to build a business plan that will withstand scrutiny. Base? Catchment population? Utilisation? Costs?
Can you do it with a twin? Yes, of course. You can also, with some limitations, do it with a single. Read EU-OPS and the ANO, they will give you the detail - but you know that already.
Remember the old adage that the way to get a small fortune in aviation is to start with a large one!