VN/Ren'Py .. but will be experimenting with other game engines
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Hitomi, Sierra, Chione, Hitomi's Girlfriend, Sadie, Sadie's mom, MC's Girlfriend, MC's Girlfriend's Daughter, MC's Rival
the 5 unlined needing names and backstory
Ren'Py is typically a VN engine, but I meant how are you building your game, not what engine are you using. For instance, View of Family is a Ren'Py game, but it's a life sim. And I ask, because as BeWilder said, you're growing quite the large cast. Now, if a few of them are just background characters who have no place in the story, then you'd be fine. However, with each character you add the chances of you successfully building a game with the VN style become smaller. The only game with so many characters I can think of is Sisterly Lust, or Good Girl Gone Bad.
Now, looking at SL you have 3 ladies who don't really need much development, they're barely developed at all. The sisters are more developed and well thought out, because they're the ones who matter. GGGB has gone on long enough that it's been able to develop some of its cast over time, but even still, the girl from the book store and her boyfriend have little to no screentime, Eric's sister is on screen a bit more, but is very much cliche. So as you can see, too many characters in a VN gets dangerous.
In a Life Sim, however, with proper design each girl gets their own individual story arc. You spend time each day with whichever girl you choose to and advance the story with them individually. Typically this allows you to date everyone if you want to, however, that's mostly because the average developer hasn't been very smart with it. You could make it so that advancing your relationship with one character will degrade your relationship with another. Its all a matter of how you want to do things.
i don't like points grinding unless it has real point in the game
Check out Milfy City. It's a life sim without a lot of points grind. You can also check out view of family, which I mentioned before. It has a bit of a grind, but for the most part it is manageable.