So I got in touch with an '07 fellow and here is what he had to say about his experience with CLEO and how it helps or doesn't with placement.
Congratulations on your CLEO acceptance! I highly recommend you attend the summer institute.
Now more specifically on to your questions. I can only relay information about CLEO assistance in placement from my own observations during my summer institute in 2007. The majority of fellows had already been accepted to a law school before the institute began. These acceptances ranged everywhere from Berkeley and UVa to more obscure 4th tier schools. There were students who had not been accepted to any law school at the beginning of the program and were placed by summer's end.
Throughout the summer, there are representatives from schools who visit the institute to recruit, this ranges from informal chats and application solicitation to more formal interviews. There are a variety of schools that do this type of recruitment. During my institute, schools included, University of Iowa, University of Wisconsin, University of Denver, UNC, Ohio State. However, there is no consistency to this recruitment, and it may be dependent upon the institute location. My brother attend the summer institute one year later, at a different location, and no school conducted interviews for recruitment purposes. Typically, the law school host institute will recruit from the CLEO fellows.
The students who had the most success with acquiring acceptances during CLEO were those who were waitlisted. I was waitlisted at Ohio State before I attended the summer institute, and received an offer from Ohio State a few days after the institute was over. I do not believe that CLEO did much in the way of facilitating my "placement." I was waitlisted early on and sent several letter, supplemental information to OSU. It was merely coincidence that Ohio State was at the institute to recruit. Before the offer, I have planned on attending SUNY Buffalo. If you are waitlisted at some schools, it is in your best interest to inform them that you intend to attend the summer institute and you remain committed to attending. This may sway some schools, since as you indicated it is your UG GPA that may be the weak factor in your application. I do remember schools like Southern Illinois University and Missouri being at the institute to recruit, and I suspect that your ivy league background would be more valued at those places than than at schools in the northeast like BC and BU--which probably has many ivy leaguers.