Firstly AFAIK you can do some stuff through the AWS console, but I'm not sure what the limitations are. Personally I have never used it (I just use the Hub for server management) so I can't really give you a lot of info.
Secondly, I have no idea how you would be able to add an existing instance to the Hub. Probably the simplest, easiest way to do it, is use TKLBAM to migrate to a fresh instance. (make sure everything works 100% before you turn off your old one).
2 (inconclusive) answers... :)
Firstly AFAIK you can do some stuff through the AWS console, but I'm not sure what the limitations are. Personally I have never used it (I just use the Hub for server management) so I can't really give you a lot of info.
Secondly, I have no idea how you would be able to add an existing instance to the Hub. Probably the simplest, easiest way to do it, is use TKLBAM to migrate to a fresh instance. (make sure everything works 100% before you turn off your old one).