Did you see my edit ?
about build retroarch indipendent cores ?
Please excuse my late response, I was painting.
It is complicated at first.
Supposedly, with every new version of Retroarch, the cores gets updated too.
But most of the times they're not.
I'm using Retroarch 1.7.5 with new and old cores. I certainly cannot tell which version of the cores I'm using.
I downloaded a zip containing cores for the Wii version of Retroarch and that zip included among them the CPS1, CPS2, Finalburn Alpha and Mame 2000 cores. So, from that zip I'm just using CPS1, CPS2, FBA and MAME2000.
For Neo Geo and CPS3 I'm using the cores from this thread:
https://gbatemp.net/threads/large-neogeo-games-support-and-cps3-tests.493767/
I've encountered many errors with sound using CPS1 and CPS2, again, can't remember which version of the cores exactly.
What I did is that I tested cores from different versions until I sort of "Hit the spot".
Remember that the Wii is quite un-powerful, and many Arcade games (for MAME) won't run as a result.
But some old classics from 1997 and backwards are compatible with both MAMEWII and Retroarch's MAME2000 + MAME2003 cores.
MAMEWII is a stand alone Mame emulator.
Retroarch is capable to emulate MAME2000 and MAME2003 cores. The MAME2003 cores are split into many stand alone cores, as MAME2003 core is too huge for the wii to handle. That's why we have Mame Core A, Mame Core B, Core C, D, E, F, G, but they're all part of MAME2003.
Bubble Bobble 1 and 2 are compatible using MAME 2003 Core B. But trying to load Bubble Bobble 3 onwards is impossible due the lack of power of the Wii.
And CPS3 roms are hit-or-miss... I never made CPS3 roms work until I found one video on youtube containing a link to Mediafire with the core and roms. They worked and now I can play some CPS3 games (have in mind that the CPS3 library of games consists of
ONLY 6 GAMES) so it's not a huge loss.
So far... I've tested roms from different sets using the Mame 2003 cores, and while there's a compatibility list in the thread I gave you above, some if not most of the roms from that set are not running for me.