Hello! Welcome to CS c:
1. Those pets aren't often available for the monthly adopts (although every so often they may be). Rather, they are usually released as part of events which go on during some major holidays and the summer! Our next event will start in mid October, for Halloween.
It's also worth noting that some sections of the adoption page give out different types of pets from month to month. For instance, the "Hatchery" has been know to give both chickens and chameleons as monthly adopts.
2. You cannot breed your pets. Instead, there is a section on the adopt page for "2nd Gen" (or 3rd Gen) pets, where site artists create the children of two out comes. You can suggest a couple to be used here:
viewtopic.php?f=6&t=34027403. You send them a trade asking for what you'd like! Most people have strict rules about what and how much you can take though, so be careful to read carefully! You can find people giving away their pets here:
viewforum.php?f=22