Dylan : most predominently male
Kendall : male only
Stacy (Stacey) : female only
Devon (Devin, Devyn) : unisex
Dylan: traditionally male (and makes anyone my age or older undoubtedly think of Bob Dylan (or perhaps even Dylan Thomas (“Whoever he was.” -Simon & Garfunkel))), but nowadays, as with so many traditionally masculine names, it’s being taken over by the girls. (WTF is up with that, by the way? Sooner or later there won’t be any boy names left.)
Stacy: Could be either. If you pressed me, I’d say it leans female (Stacy Keach notwithstanding).
Kendall
Devon
Have no idea, since I’m not familiar with these names. If I had to guess, I’d guess female, because far more often it’s parents of girls that feel the need to get creative and cutesy and original when naming their babies.
Dylan – I’ve only met boys, so that’s all I think, but I’ve seen girls in birth announcements and such. I don’t like that.
Kendall – It seems more like a girl’s name (it’s my mom’s maiden name), but I’ve known about equal number of boys/girls. I once met a boy who spelled it Kyndal, which I thought was awfully girly (and bad).
Stacy (Stacey) – Totally girl to me. I’ve never met a male Stacy, and only personally know of Stacy Keach for a male.
Devon (Devin, Devyn) – The first time I ever heard Devyn, it was on a girl, so that’s what I’ve always thought of it as. Since then, I’ve met more boys (usually Devin). I still think of it as a girl’s name first though.
Dylan - Male
Kendall - Female, but I know a male one
Stacy (Stacey) - Female
Devon (Devin, Devyn) - Male (presumably black)
Dylan - male
Kendall - predominantly male
Stacy (Stacey) - female
Devon (Devin, Devyn) - male, except maybe the last spelling
For:
Dylan Mostly Male
Kendall Female
Stacy (Stacey) Mostly Female
Devon (Devin, Devyn) Mostly Female
Aha! And here I think we have the answer to my unwritten question.
My youngest child, my son, is named “Kendall”, which at the time I could not have imagined as a girl’s name. The only two Kendalls I’ve ever heard of are “Kendall Gill”, a former NBA basketball player, and “Kendall Gammon”, a former NFL football player. Also “Jason Kendall”, a baseball player, and what he was actually named for, “Kendall-Jackson” the California vineyard (a friend of mine had just had a son named “Jackson”. I had never heard of a woman named Kendall, real or fictional.
And yet, very often, people assume my child “Kendall” is a girl when I’m registering our names at a ticket counter or something. At first I thought it was because he has two sisters and I’m often carrying a bunch of their girly stuff. But then I got to noticing that it was always women who make that assumption. Yet neither I nor my wife could figure out why. Normally we associate name genders based on the first person that comes to mind, which is why I can’t think of Dylan as a girl’s name even though I know two girls named Dylan (one a child and the other now finishing college), since I think of “Dylan Thomas” and “Bob Dylan”. The “famous female Kendall” eluded our research though.
FWIW, the male Kendall I know is a large hairy redneck.
Dylan - only heard it applied to males
Kendall - it SOUNDS like a woman’s name, but I know two men named Kendall
Stacy (Stacey) - I do know male Staceys, but I wouldn’t advise giving that name to a boy
Devon (Devin, Devyn) - Predominantly female, but I have known a male Devin
Dylan - male
Kendall - female
Stacy (Stacey) - female
Devon - male
Well why didn’t you ask that, silly? 
Yeah, Sarah Michelle Gellar played Kendall Hart on All My Children. Daughter (by rape) of Erica Kane, played by whatsername, that never wins the Emmy…Susan Lucci. SMG, of course, later went on to play Buffy in the television series Buffy the Vampire Slayer.
FTR, I never watched AMC and I know all this. I am a Buffyphile, though.
m
both
f
m
Dylan - Male
Kendall - Male
Stacy (Stacey) - Mostly Female, but a few males
Devon (Devin, Devyn) - Male, but I’ve encountered one female with that name
I need to change my answer: I do know a Kendall (male). It’s possible I’m acquainted with others but only know them as “Ken.”
Dylan - Male
Kendall - Female (or Black male)
Stacy (Stacey) - Female
Devon (Devin, Devyn) - Female
Curious the strong split on Devon in particular. Wonder if that’s generational.
It’s pronounced like “Devin” here, maybe that has something to do with it … similar to “Destin” or “Dustin”, a male name.
To add to my previous response:
I don’t think I’ve ever known a girl named Kendall. Several guys with that name, however.
I’m female and from the south.
Dylan: Only M
Kendall: Predominantly F
Stacy: Only F
Devon: Predominantly M
ETA: I’m male
Dylan - Predominantly M
Kendall - Only F
Stacy (Stacey) - Only F
Devon (Devin, Devyn) - Predominantly M
Dylan - mostly boys, now some girls. Not a grown man’s name unless he’s an actor or dead poet.
Kendall - Dog’s name or maybe female
Stacy (Stacey) - female (formerly male)
Devon (Devin, Devyn) - used to be male, now mostly female