Depends largely on if Chad gets over his ego trips, comes back down to earth with the rest of us, and gets a whole lot of hot air and terrible ideas released from his brain. On Freddie’s side, if she gets over her own off-screen parental issues as I doubt that her relationship with Dr. Facillier was any better than that of the Rotten Four’s or any other VK’s; maybe not outright abusive like Cruella, but certainly absent, negligent, and a firm practitioner of “prove you’re worthy of my love” because Villain Parents found that’s a GREAT way to make sure their kids have the best chance of taking over for them, while also not realizing they’re better off without their parents in their future Evil plans.
If those two grow up and lose the worst parts of their personalities and issues, then they’d make great parents!
Chad, I imagine, would be the father that is highly loving, active, and supportive of everything his kids do, being there for them with whatever extra-curricular activity or adventure they’re up to, along with defending them (with his fists, if need be, and the target is socially acceptable like a fellow father).
Freddie, on the other hand, would be largely his anti-thesis, the calm, snarky, stabilizing force to his boundless enthusiasm and pride. She’d be the one to seriously sit their kids down and talk to them about the important lessons in life–you are not as great or as important as you think you are; you can’t ace everything you try just because you are really passionate about it; and no, bringing singing shrunken heads to the talent show will not help you win first prize by virtue of novelty. On the flipside, she will be one of the most loving and attentive parents you could ever meet, showering her kids with affection (sometimes too much when something bad happens to them, to the point that even Chad says she might be overdoing it), being there to comfort them, and help them plan elaborate revenge ploys against the other kids that wrong them in some way.
(They’re legal! Mostly. In certain states.)
For whose the more involved and active in raising their kids, it’d be Chad. It’s actually a large part of my headcanon that Freddie and their kids, biological or adoptive, learn firsthand how much it sucks to have a Hot Dad/Husband, because nothing is quite as attractive as a forty-something male who keeps in shape, can carry several pounds worth of childcare supplies with ease, and be perfectly willing to make the kids a delicious, healthy dinner, bathe them, and read them a bedtime story good night.
You could say that overachieving and going the extra mile for anything they love is a genetic trait in Charmings–alongside the great teeth.