Doublewide non-chess-variants? I'm not too familiar with halma or the
other one you mentioned.
I gave up those games long ago when i realized that the tactical element
predominated too much over the strategical. Before then, I was legendary
in 'Lines of Action', a game whose rules I no longer even remember.
I suspect that doublewide ncv is generally uninteresting. In fact, my
opinion is that doublewide chess would be uninteresting without
doubleking, for highly elevated values of 'interesting'.
By that, I mean to say that Ddoublewide with just one King is
automatically and by definition no playtest needed a difficult game and
interesting to play. But so what? There's nothing special there, just
more of the same.
My personal opinion may not be shared by the majority, of course.