I am aware of BP's possession of such records is existent for the 80s series and The Alvin Show. Excluding the 80s series' use of songs which are now under licence, why can't BP release episodes that use original songs or ones in the public domain? Viacom (which has distribution rights for both the Alvin Show and ALLVIIN!) has released full season/series sets of shows they have only distribution rights to (i.e., The Last Airbender, Full House).
I am also aware that the distribution rights for the 80s series is tricky. Ruby Spears (distributor for first 5 seasons) and the other main distributor for seasons 6-9 are now both owned by the same company.