Typically, RIL only needs the APN, user name, password, authentication type, proxy server, and proxy port to establish the data connection for all types(supl, data, mms). And the reason of creating the ril.dta.apnSettings is that RIL need all apn settings(inlcude supl, data, mms) at the same time.

The mmsc, mmsporxy, and mmsport are only used in MMS service, but not in RIL. That is why we don't need
to include the mmsc, mmsporxy, and mmsport in ril.data.apnSettings. Even in current design, RIL doesn't do anything while getting the mmsc, mmsporxy, and mmsport information.