Originally posted by JohnMK
Roland, he means CB shield i.e. "National Province" over the province you take in the peace treaty. Therefore, your point is moot. 
On question #2, you don't get the BB. Your allies do for the provinces they receive, not you, regardless if you're the one awarding it to them.
1. I knew it sounded too good to be true. What justice is there in that? If the AI players have the audacity to Diplo. Insult me, I should be allowed to take territory from them without becoming an international pariah. Guess everyone hates an empire ...
2. Hmmm ... if Grunthex is right, then it would appear that you could gain territory at a cheaper BB rate by helping a vassal in a war, making sure THEY get the territory YOU want from your enemy, and then eventually diplo-annexing them (the vassal). You'll only get 1 BB / prov. vs. 2 / prov. But then, this all hinges on your vassal being intelligent enough to besiege enemy territory and not signing a separate peace for hard cash.