You can get old school arcade games up and running in a day or two.
Theoretically yes, but it’s unsupported. If you run into problems then you’re on your own.
Blueprint has it’s limitations, but for the most part you can do quite a lot with it. You’re unlikely to find a limitation if you’re just making basic games.
Possibly, but if in doubt, contact Epic. This is kind of an edge case since the game itself isn’t sold, but used to advertise other products.