You could just play the Arcade versions instead via FBA (Final Burn Alpha) the arcade versions run on Capcom System II hardware (CPS2)
1996 X-Men vs. Street Fighter (CPS2 Arcade) Saturn, PSX
1997 Marvel Super Heroes vs. Street Fighter (CPS2 Arcade) Saturn, PSX
1998 Marvel vs. Capcom: Clash of Super Heroes (CPS2 Arcade) PSX, Dreamcast
2000 Marvel vs. Capcom 2: New Age of Heroes (Sega NAOMI Arcade) Dreamcast, PS2, Xbox [The Dreamcast was a cheaper home console version of the NAOMI system] DEmul or Makaron should do for emulating the NAOMI system, or you can try to play the Dreamcast version (Not sure off the top of my head what version is going to emulate best, I tend to play that game on my Dreamcast directly)
Anyway I recommend using http://psxdatacenter.com/ to find the PSX games you want to play as it has settings for each game in the list, just under the screen shots for the game (after you select the game on the site)
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