Quick reply...
What about adding to deb dependencies:
provides: osso-lmarbles
replaces: osso-lmarbles

It should allow uninstallation of non-free osso-lmarbles and Osso-graphics-game-lmarbles without disturbing mp-fremantle-generic-pr, and mokomaze is only slightly larger than osso-lmarbles and Osso-graphics-game-lmarbles taken together, so it would be just replacing one non-free component of Maemo with a free one, which looks/works better.

Are there any problems with this suggestion?