Sandwiched beams on notched posts for deck
I agree that your posts should not contact the concrete as concrete wicks moisture. Check out Simpson Strong Ties for various post to footing connectors.
In order to knotch out the posts, make sure the posts are 6x6 posts as 4x4's are not wide enough. Also, you may not have permits required, but safety is safety. Where I live, a cantilever can not be more than 2 feet when using 2x10's. Imagine 10 people, each 200lbs, standing along the cantilevered railing. (2000 lbs on a 4 foot overhang). It may not break off, but it creates a lot of upwards force on the ledger board fasteners (the beam acts like the pivot on a teater-totter) and I've seen them fail from this.
Good luck. Build Smart! Build Safe!