Yes, that will work. The PCMIDI is essentially a clone of the MusicQuest card, so it will work just fine. The PCMIDI will operate in UART mode when using it in conjunction with SoftMPU, while SoftMPU emulates Intelligent mode in software.
Regarding the Roland RA-50: it's almost 100% compatible with the MT-32, apart from the issue with the All Notes Off command. That command is used by some games to silence all notes at once on a particular MIDI channel. The RA-50 filters this command, which results in notes being stuck. There are 2 ways to circumvent this issue:
- Modify the RA-50 to bypass the chip where the filtering of the All Notes Off command occurs
- Convert the All Notes Off command to separate Note Off commands
The aforementioned hardware modification does the first, whereas SoftMPU/HardMPU does the latter. It keeps track of which notes are active on each MIDI channel. Whenever an All Notes Off command is issued on a particular channel, it sends separate Note Off commands for each active note instead. Unfortunately, as you need to keep track of the active notes, it means that you can't fix the issue by sending some SysEx messages in advance. So if you don't want to modify your RA-50, SoftMPU/HardMPU is your only option.
However, I'm actually working on something to provide the same functionality as the /RA50 and /DELAYSYSEX switches of SoftMPU, but doesn't require you to run a software TSR on your PC. It's a piece of software that runs on a MIDI processor instead, that you put in between the MIDI interface and the RA-50/MT-32. It's already working nicely here, but I need to find the time to polish and finish it before I can release it.