Every Universe isn't the same. It's how the DOF universe works...
Jokes aside, the asset(Vagina) I use is for making good animations of the Vagina. It is so that there isn't much clipping in that area while making animations. The asset gives me a lot of vagina physics. Unfortunately, it doesn't give me the option to change the color of the lips. I thought no one would mind. This is the first time someone has pointed it out to me. I guess I can look for ways to change the color in the future.
There's really no need. It looks good, and fits the palette and aesthetic of the rest of the novel.
In short, your VN already looks great, in all aspects, and nothing needs to change.
OK harem and swinging. Not interested at all although I've heard that the dev here thinks swinging is more lesbian shit so that also puts me out of the game. There are no lesbians in my harem. It's the same thing as having a direct NTR so the game is not downloaded or if it is downloaded then the game is deleted.
Right from the very beginning there is a choice between Normal and Hardcore mode, which it explains as being the you're the only guy in the harem or the sharing/swinging options respectively. If you don't like that content, simply choose appropriately.
As for any of the other choices, they're pretty clear. You can opt out of any and every thing you don't like.
Either way, seems like you haven't actually read any of the VN since you stated "I've heard" as though you have no firsthand knowledge about what's actually in the novel. That being said, perhaps you should actually go through it before you decide to comment on what can be found within.
Does anyone else have lag in the sex scenes?
Nope; not a single problem. Everything runs smooth all the way through.