You can do the corners by making up a "L" shape and fixing this to the posts then just butt the cladding upto this.
If you skin the outside in 12mm ply you can do away with any diagonal bracing to the infill studwork, and just use a few on the oak for decoration.
To hold it down set some stainless studding into the concrete with a nut & plate washer on the end, let this come up through your brickwork, through the wall plates and use another nut & plate washer to tighten it down. You don't want steel pins in the corners, the half lap joints on the wall plate should have a mortice through them with a matching tennon on the end of the posts to pin the joint together and locate the post at the same time. This is the easiest way to do the wall plate corners, the other option is to M&T joint them together with a timber peg and then have a second mortice for the post to locate into.
You may find
this of interest
Jason