It’s true that by editing facial features and eyes based on cards like SolityL’s or kyonko’s, you can create fairly high-quality cards.
I agree that reselling without any modification is not a good practice, but would selling something like this also get me in trouble?
I don't think there's a problem, as long as they're edits or creations with their own style, because you wouldn't be the only one using overlays, nipples, irises, or tattoos (etc.) from other cards for your own work.
Now, regarding sales, I really wouldn't know how to advise you because I don't sell what I make. However, I can assure you that selling cards is viewed with neutrality, leaning towards the negative. I say this because of the same policy Illusion Games had with creations made in their games (no sales). Since the company no longer exists, those who seek income this way can circumvent this rule, but the community itself doesn't fully accept it.
Although I'm more pragmatic, I don't like selling cards individually, but if it's a Patreon-style subscription, I might even give it a try. But as I said initially, you have to infuse it with your own style (I have to like it) and put a lot of work into the clothing and even the smallest details (something I'm currently doing is modifying the detail masks of some garments based on how ABCEEFG uses Maintex to highlight the nipples underneath, Kunaboto-style). There might be people interested, and if I want, I'll sell it, and that's it.
If there's a problem, the only possibility is that SolityL notices you're using their Zipmods on cards you sell and gives you trouble for it.