edit and save multiple files for each phone, upload the files somewhere, set the phones to provision at location uploaded, have the phones setup according to mac address. is this possible?
You enumerated what needs to be done, so I don't understand "is this possible" question.
You can have single configuration file per phone.
You can have common configuration used by all phones plus smaller single configuration file per phone used to setup phone specific things only.
You can have simple database and trivial application (or even just script) that can craft configuration for particular phone (based on database content).
Other odels are possible as well.
In short - phone can be provisioned by configuration. How you will create and maintain configurations is up to you - just consider your environment, requirements and skills (or budget).
I know there is some $MA string to be used somehow, but haven't found out how?
It's just macro (other macros exists as well) that can be used in SOME OPTIONS of configuration file. For example in Profile_rule (to note most common place of use). It's replaced by value during use. $MA is macro replaced by phone's MAC address.
