Talk about clueless. Duh.
First I suddenly realized that I can't use dynamic lists since that'll query the DB and since I'm editing in memory my collections, well every query will show what's currently in the DB and not in memory. So I have to stick to my collection.
What I hadn't realized at the time was that by creating a property (Fullname) on the entity and databinding the collection directly to the datagrid, that it automatically generates (besides all the entity fields) the column with the property Fullname I had created!! I never saw it until I horizontally scrolled the datagrid by mistake and voila! There it was! I felt quite stupid to say the least.
So all I had to do now was set the datagrid's autogenerate=false and individually bind the columns I wanted to see with the datagrid's property builder. It was a piece of cake.
Anyways, I thought I'd explain this in case someone out there besides me didn't realize this.