[lucasmullens]

It might be worth considering just changing the rules for the pawn to deal with this. It's hard to tell what it means to move "forward" on a board like this, even after understanding the indicators.

Maybe pawns could just move horizontally/vertically and attack diagonally, regardless of color?

[frading]

That's an interesting suggestion.

The pro is that it will simplify things, remove visual and cognitive clutter.

The con is that we stray away from classic chess rules, which I'd still like to avoid as much as possible.

I will think about it. It may be possible to allow as an option.

[paipa]

Your constraint should be that if the board is the special case of regular chess, the game should play exactly the same. Allowing the pawn to move towards any side is too much because it would violate this principle.

Perhaps define forward as the direction(s) which, when extrapolated as a rook, would reach the opponent's backrank. If it doesn't exist, the direction(s) which, when extrapolated, terminate on the opponent's half. This would allow extra freedom to pawns in some funky topologies that can occur in your game, but generally follows the principle of least surprisal.