Ditto can breed with ANY AND EVERY POKEMON unless they are in the No Eggs group. Period. Here's a list of the Pokemon that can't breed at all:
http://www.psypokes.com/dex/search.php?type=egggroup&egggroup=no+eggs
Ditto can breed with males, females, genderless. If the man at the Daycare says that your Ditto and Hitmonchan
(Charizard, in your case) "don't seem to like each other," this means that they WILL breed. It just may take longer.
The ONLY time two Pokemon won't breed, if they are incompatible, is when the old man says "they prefer to play with other Pokemon."