I know the characters you're talking about ...or at least about as much as you do. Saw some people making fun of them. They look pretty dreadful. XD
Loved Casper too! It's pretty hard to beat those old Harvey comics.
I think this era off the Avengers is 68-69 or so. They have a real charm to them. Especially some of the tropish dialogue. although...it wasn't a trope yet when these where published