I feel Himbo is more apropos than playboy given that Asahi doesn't
intentionally put the moves on people, he's just kind of an airhead who doesn't understand boundaries and rizzes up people by accident. I mean he also says "Yes" to anyone who asks him out (at least for the girls so far) so Himbo feels appropriate for that as well given if he was a girl who said "Yes" to any guy who asked "her" out they would probably call him a slut (granted he seemingly never puts out so he's a very dry slut).
I don't know if Japanese has a term that could apply for Himbo and I'm not blaming the translation, just weird fridge thought that intruded into my brain.
Are they friends or dating? Everything is phrased ambiguously.
They are "more than friends, less than lovers". Think of it as a trial/probationary period for Asahi to figure out if his affection is romantic or platonic.