On your first question, I think there is a little confusion. The exams are for to to become a LEED accredited professional.
To get a building LEED-certified, you have to document all the credits and prerequisites you want to earn via LEED Online.
To get the other 15 hours, you can look for online courses through the USGBC site. We are offering a webinar on LEED-CI later this month that qualifies!