Ahhh, the Y body. Idk if there’s a home for them out side a Facebook group.
Nice cars, I dig them. Someone here maybe able to answer the questions you have.
I THINK the fwd LeBaron and Dodge Daytona, Plymouth Laser type cars are J-body. Obviously no relation to J-body Mirada/Cordoba. Not sure what body an Omni is. The larger models were designated LH.