It's natural, in my experience, to really develop characters. No one is technically "normal", as we all have our quirks. Now, if your characters are exploding with emotion like rabid anime characters, then there's reason to tone them down, but besides that, so long as they can have a moment where they clearly are just a human being like everyone else, they should be fine.
Well how about picking what makes them too strange and taking those qualities out?
I'm sure you'll be fine. All my characters are weird, so I make the rest of the people strange as well. Better to have every character be strange in some way than have strange MCs and everyone else be perfectly normal Joe.
Personally, I wouldn't think of making "ordinary" characters, since someone's flaws/weaknesses/strengths/talents make them less than ordinary. That said, never aim for making "ordinary" in anything, since that's nigh impossible.
Try to make them like the "normal" people you know. Also, there's hardly anything wrong with an over-developed character unless they're a Mary Sue. Try not to shove all the information at once, but space it out.