The answer to your question is call FM tech support. They spent a few hours with me while making the full installation. I also purchased a t2.Large Instance with 8GB memory plus two volumes for storage. 30GB for system and 40GB for data and backups. If you are new to AWS, I recommend paying for Developer support. So far so good. Keep in mind that networking speeds will suffer as compared to local ethernet.
I decided to not go with the FMCloud server services as I was told that the user licenses and server license we currently have are not useable with that cloud system. (Tip: Windows Server)
I would be interested to hear from others who are using AWS to host their FMS.
How do I migrate my server account to a cloud account?
The AWS Marketplace as a FileMaker Cloud BYOL option that allows you to convert. But consider it carefully; if you don't currently have your license as "filemaker licensing for teams" (FLT), using the BYOL conversion will convert to FLT. You may or may not want that.