It sounds like submissive urination to me. So I would just be ignoring him completely when you come home and only paying him attention when he is calm. This has nothing to do with toilet training because, as you stated, he cannot control himself. So if you want the behaviour to cease will have to try to make sure he has no reason to do it.
I.e. ignoring him when really excited, avoid yelling at him too harshly (scold yes, loud screams no), making sure visitors ignore him when they come inside etc.
As for the barking at the front door I would rope someone in to help you and practice him being quite. For example have your dog on lead, get your friend or helper to ring or knock on the door. When you dog begins carrying on gently turn him away from the door and say "enough" or "thankyou" or something that you can use in the future as his cue to be quiet, and keep turning him away until he is quiet and then reward. Then rinse and repeat
It will take a little bit of time but it will be worth it in the end
"In order to really enjoy a dog, one doesn't merely try to train him to be semihuman. The point of it is to open oneself to the possibility of becoming partly a dog." - Edward Hoagland