as to the Dizzy's thing as far as I am aware the only way to really get a feeder to eat the magic doughnuts is to hose feed them the magic juice so having a different method would be nice
You should be able to persuade a feeder to eat a doughnut when on a date with her at Dizzy's Delightful Doughnuts. Once she does, she becomes addicted and will always stuff herself with doughnuts whenever you go there with her.