Call me speculative, but Hamasan = Yusuke Takahama?
I was listening to the Shin Nihon Pro Wrestling set from snesmusic. I thought it sounded like Takahama's music... then the penny dropped and I noticed Hamasan could well refer to Takahama. I checked other games developed/published by Varie and saw that Nage Libre was one of them, which Takahama worked on. All that considered, I can't imagine Hamasan being anyone else. Unfortunately I cannot find anything on Takahama's site to confirm that he composed for Shin Nihon Pro Wrestling -- it might be there somewhere but I'm blind and can't see it, he doesn't have an explicit list of games he worked on that I can see.
EDIT: another Varie game here composed for by Hama San
http://project2612.org/details.php?id=557
GMCL also says that Takahama goes by the name 'Hama' sometimes.