Well if you want music that's your only option - WiiSX can't stream audio, and Pocket Fighter is one of the many games that has that for music....
Found it from the 2nd link that shows up by typing "retroarch wii" in the google search engine and from there you should see in the top right hand corner of the website it says "DOWNLOADS (STABLE)". Retroatch wii is somewhat easy to setup.
For starters, the menu looks like something out of MS-DOS (not accessable like WiiSX, Wii64, VisualBoy Advance GX, SNES9xGX, FCEUGX (the NES one), and GenplusGX). And when I selected the CPS2 core or the sfa3.zip, it brought me back to the loader.Well you're stuck with no music (long loading times....missing frames of animation) I'm afraid - the games you mentioned above that have sound use the PS1's sound chip (though I'm surprised MVC does! Skullmonkeys and Crash certainly do anyway). Final Fantasy VII is another. But Pocket Fighter streamed the music from the disc (aka CDDA), something WiiSX can't do...
Give Retroarch another go! If all you're interested in is the CPS2 games like Pocket Fighter and MVC, get onto the menu, change core to CPS2 and you're done - it'll stay there unless you change again, then you've got perfect arcade games (don't get me started on the PS1 versions of MVC and SF Alpha 3, I had those on the actual PS1 back in the day..) and loads more to choose from too. It looks difficult, but imo if you can run WiiSX, you can get your head round Retroarch!
- Horrendous looking gui (compared to the GX emus for a start). But not that much less accessible, and if you're using a loader (Wiiflow? Masterpiece pack?) in my opinion it doesn't matter as much anyway... Assuming you're using the wiiflow masterpiece pack the core should be fine - your romset on the other hand might not. You need the correct romset of Final Burn Alpha, NOT Mame. Yes it's a picky bastard, but once you've got them, then put in the right directories and so on, it should run a treat. A good idea if you're getting pissed off with it is to grab the PC or Mac version of RA and try the roms you've got on there - if they don't work on FBA on that, they're not gonna do on the Wii version either, but trust us, they do work!Just saw this.Doesn't it just...
Good to hear you got them working! As for difficulty settings, press the home button when your rom is loaded and go into core options (or something!
A. It's been a while, and B. I've not got my Wii to hand) There you should find a setting that says Dip Switches (or similar). Switch that on, go back into your rom and you should be able to change the difficulty. There's a possibility, it being an arcade game and wanting your money, that the lowest difficulty is still a bit tougher than the lowest found on a console version, but practice makes perfect and all that! 
