No, MikroTik doesn’t support upgrades from one level to another. You can get higher license on device, but you have to pay full price. I don’t like that, but it’s their decision.
If you mean that they would configure router for you, the answer is no. If you can’t do it yourself, you need to find someone else.
3,4) RouterOS is known to not support everything. If you want to be sure, download CD image and try to install it. It will run without any limits for 24 hours. Or there’s free L1 license, it works forever, but has some stuff limited.