I appreciate your position, but in my humble opinion, your argument is flawed because your premise is wrong:
I don't think one can separate the scheme from the gameplay when talking about design... meaning the 2 independent rocker D-pads (UP/DOWN) were always linked to two independent characters in the G&W games., while the 4-POSITION buttons were linked to one character.
Lion uses 4-POSITION buttons to control two independent characters. Manhole uses the exact same 4-POSITION button configuration to control a single character. There is no direct correlation in these cases between scheme and gameplay when it comes to design. Otherwise, by your argument, Lion should have been implemented with rocker switches since it uses two independent characters!
If you want to focus the jam on exploring game design based on the idea of moving two characters/objects independently, then you should define that as the design constraint and not the control scheme.
Please forgive me for being somewhat pedantic here, especially given the nature of this jam and your well articulated goals for it, but I think the question that started this thread illustrates that there is a mismatch between your coupling of the control scheme with the intended design constraints.