On the whole, nowaypablo basically hit what I'd touch on.
I'm less in-the-know of Wii titles than I'd like to be. As far as solo adventurous games that inspire wonder years later, will bring on nostalgia, and a potential for learning about older titles, then Zelda (Twilight Princess, or even Breath of the Wild, if that's out for Wii). and Smash Bros Melee. But IIRC, you have young girls that you may want avoiding violent games (though, I think it's more like to be anti-social than violent). Otherwise, I'd be all for Mario Kart - Mario Party (the link is to 9, but there is an 8) is always a safe bet with groups and kids (if you want a title to play with the kids and easy to pick up, too).
Either way, if they get excited and interested, they are bound to develop keen hand-eye coordination.
Also, played them a handful of times, if at all, but I think they'd enjoy Just Dance or the Wii Fit assortment. I have an inclination you'd like the titles/games referenced in this paragraph more than the top, lol. The top is where the "best" are, down here is the "safe" are. But if you have any interest in gaming, then the above can also be a shared experience.
Can't link Just Dance, since it's formatting is similar to Hubski's and keeps breaking. But there are a few of that released for Wii. Typing in the search bar of the nintendo site will get good results.