Since the OPL3 (and OPL4 FM part) are basically doubling the OPL(2) channels, it should be possible to play back tracks using two OPL or OPL2s on OPL3 or OPL4.
The biggest obstacle is that the OPL3 only has one rhythm section. Initially we could simply only support the rhythm of the first OPL, and hope most VGM packs don’t use it on the second.
However as an extension to this we could also OR the rhythm sections together. This is slightly more involved since we need to make sure the channel frequencies of the rhythm channels are set up and restored correctly when the rhythm mode is enabled on either or both of the sound OPLs.