Sadly there is no way to add teams without a lot of crashs... The only to add a ( or 2 ) team is to rename All-Stars team ( Sounds/comments will stay as Brett Hull original )
JHL is a hack of an unreleased game ( 99% finished but not 100% ).
When a team is changed : Name, city name, rosters, colors of sprites, team comments are changed , all are in a different places in the rom. Adding team without crashing PlayOffs and Season mode is near impossible ...
The better way could be to ask the source of the game to Chris Oke and Ed Ringler ...