Spain should have quite a few claims in Central America. You can always try to declare on someone you got claims on, then add to your war targets until you the pesky nations attacking your CN.
Sure, the war may blow up - but you should be easily able to beat them and feed them all to your CN.
They do but the countries that are attacking New Spain are in North Texas or New Mexico area.
Also I just got CB not too long ago because you have to colonize Venezuela area to get the Mission for CB.
Problem is going to be resolved when I play again (it is a Multiplayer game and I have a human England player as well so we have to get together to play. He is having same problems in North America).