With the Mondo release as a picture source, maybe the original mono could be reconstructed to sync with the uncut version.
Did the 1991 LBX LD have the sync problems too? Also, if the old VHS tapes were uncut, does that mean the missing scenes could also be on the old CBS/Fox LD? It's non-CX analog, but it is English mono...
LDDB also claims that the Japanese LBX disc is uncut. There's a copy for sale, but like most Japanese LDs, it's pricey (about $43, plus the seller is in Japan).