Obviously, the SWCDX2 can if you have a 32M one. If you forked out more for a 64M you don't need it. Not sure wheter it is standard RAM though, I have never opened it.
There is no reason to upgrade an SMG. With its 8 Mbit, it can run every game except SF2CE. You'd probably have trouble finding the appropriate RAM for it, and it's soldered in place as well. Not worth it for that one game. Just buy it if you want it, it's not hard to find and it doesn't cost an arm + leg either.
I believe I read something about the SMD working with RAM from a Pro Fighter or something like that. It was an SNES device, I know that. If I find out for sure which one I'll tell you so you can buy one just for the RAM (hell, I'll buy one for when I find an SMD).
As for MGD1, I don't know anything about it. Good luck even finding the MGD1, much less upgrading it to 8 Mbit so you can run Dragon Warrior IV.