I recently transferred my mossoms to my wife but I have Slack left over. Can I transfer that to her too?

Sorry Knocks, but resources are not transferable. If you want to use those points for her, you can take 2 of the mossms back and breed them (if you have 1200 of it), and then pass them back with the baby, but you can't transfer the resources :).

Have fun,
Trinity