So maybe in the 1st minigame you & Eve are in a map of the house and trying to both get from Eve's room through the house without Mia seeing you. When successful you get a motorboating Eve scene.
Later while out with Eve you get a 2nd minigame where you and Eve pick up Nina from Ember & you have to then get back through the house with Eve & Nina to Eve's room without Mia catching you. If successful you get a Threesome scene with Eve and Nina.
Then later that night you find out Nina is friends with Becca who lives just a little ways through the forest. So you, Eve & Nina have to sneak back through the house past Mia and through the forest while avoiding a bunch of Wendigos to get to Becca's house & if successful you get a scene with Eve, Nina & Becca as a reward.
Also you could have a minigame where you go to Eve's room one evening and find out Helen has stolen all of Eve's bras and panties and hidden them around the house and back yard. So you then have to go all around the house and find all Eve's bras and panties while Helen & Mia are walking around without Helen and Mia catching you. If you successfully return all Eve's bras and panties back to her, Eve gives you a sexy time reward.
This minigame idea has some promise haha