i love les byler so much, but I feel like people tend to forget it's still byler. Michelle is still Michael, they're still dense and emotionally repressed teens who have a thing for their pretty hazel eyed best friend that they refuse to acknowledge.
On that note, imo, I feel like Willow is more confident than Will. Not like significantly, but probably more comfortable in her identity than Will is. Will was bullied and called slurs his entire life, by both his father and the people in Hawkins, because he was shy, quiet, and loved art. Basically, he wasn't considered "boyish" or man enough.
Willow, however, is still shy, quiet, and artistic, but that's more socially acceptable for a girl in a small conservative town in the 80's. She was still bullied, still called names, but I do believe that her bullying was less because of the town's image of a queer and more generally focused on her background and quietness.
Also, referring back to the very first point, les byler is still byler, neither of these girls are entirely "feminine" by society's definition. I don't see them wearing heels or what is considered "girly" clothes, wearing full faces of makeup, gossiping, or playing with dolls. I feel like they'd both be tomboys, sort of like Max. They'd still be incredibly nerdy, they'd love video games, comics, DnD, basically all of regular Byler's interests. That would be another reason they'd get bullied, for liking "boy" stuff.
With Michelle, her style as a kid (S1-S2, maybe S3) is similar to Nancy's, but with more purple and a darker blue. Something you would wear to church, honestly. It isn't till she's a teen (S4) where she gets more into her style. I'm a firm believer in emo lesbian Mike Wheeler, so I'm a firm believer of emo lesbian Michelle Wheeler. The Hellfire shirt, paired with either tight skinny black jeans (or jorts???) and beaten up sneakers.
As for Willow, her style is more baggy. Due to the influence and abuse of Lonnie, she would wear big, oversized jackets and try to cover up her body as much as possible to not spark any "provocation" (again, Lonnie). Instead of the bowl cut, she'd have a bob with the Byers bangs, but towards S5 her hair is slightly longer, so it just barely reaches past her shoulders.
While I do believe that their dynamic would be different, in the end they are still the same characters. Michelle isn't this flirty girl who's always hitting on her girlfriend because she's still Mike, so there's still some awkwardness and internalized homophobia inside her. Willow isn't this popular, skinny strap girly girl because she's still Will, there's still this deep fear of growing up and attracting attention inside her.
God I could go on and on about les byler I love them so much my baby girls (*˘︶˘*).。*♡