I'm glad you say they are nice dogs other than this problem, I am getting a Crested in a few months
Getting him neutered would certainly help with the marking.
The thing with breeding is papers can often mean nothing, it proves that he is a purebred Crested and to be honest, it's fun to flash around in front of friends (

) but it doesn't prove he is 'good enough' to breed.
By good enough I just mean that only the 'best of the best' should be bred from and to prove they are the best they should be shown in the conformation ring.
You then have to study up on the
breed standard and find a compatible b*tch to breed him to, meaning she should the have opposing as well as complimenting qualities to him... So if he is a little too heavily boned then you need to breed him to a b*tch that is finer boned, if he has a raised foot you need to breed him to a b*tch with more of a hare foot and so on...
Then there's the health testing, but that's a whole other chapter.
If you do decide that breeding is what you want to do I would love it if you would come back and discuss it further
As for the pottying in the crate, have you considered leaving him somewhere like your kitchen during the day?
I bought a baby gate a while back and it's the best thing I ever bought... I used to come home to wee and poop everywhere but now I have given them a bit more freedom in the kitchen they haven't done it once.