only missing Molly non succubus erin and Eric how do I get erin also the game dosent end so I can't restart 

To get Erin you need to do the monster caching quests intel you get a prompt that lets you say "it sounds fun". Using that options will let you talk to Erin first on the street then in the monster barn. In the barn frets ask about chakrms them tell her about your magic. Win Erin says "um... I guess I'm just avoiding the topic"(not full comment) cast flirt. That leads to a sean in your room that let's you enslave her, you jest have to ether brake your promise or cast grapple.

For Eric you'll knead to continue the monster quests with Erin having a different personality. You'll probably mess up on the first fuse trys without more intell.

So long as you enslaved Jane by turning into and then casting confuse on her during the extra class for transform with Molly then all you have to do is talk to Jane again in her classroom. If not you will have to take the extra classes with Molly until you finished that lessen then win you are back to your original form talk to Molly in the itome shop and cast grapple on her.

As far as not being able to restart you could ether start a know game then save it in anther slot or go for one of the finished endings. The one that I go for is to get the mysteries book then get a note for Jane's class then giving the book to her after the class. (must ether be a boy or have high levels of love with Sarah)

thanks