coax is coax - it's a cable. Short for coaxial... co- meaning "two" (conductors in this case) and -axial meaning "axis". Thus, two conductors mounted about a common axis.
RCA is RCA - it's a connector. Both analog and digtal signals on coaxial cable can be terminated in RCA connectors.
XLR, as you know, is also a connector.
In terms of what yall are trying to communicate, you're talking about two types of signals carried on coaxial cable terminated in RCA connectors. The answer, you want to send an analog signal out of the RCA jacks on the m248, via coaxial cable, into the analog inputs on the minime, which are XLR connectors. [sarcasm]After going through the magic smoke inside the minime, and passing by the calpots[/sarcasm], you want to take the digital AES format signal from the XLR output jack on the minime, down coaxial cable, and to the RCA connector input on your deck's 7-pin cable.
Sorry, I'm all about some correct terminology. +T's around.
Kevin, you going to email me those MSG pictures any time soon?