Good work. You certainly put a lot into that post.
As long as I have followed football there is one constant. Head Coaches bring in "their people". They bring in guys they know and trust. Guys who will coach or teach their system.
In the case of Cross, he obviously stayed on his merit from his previous work. Unfortunately, he did not have a 3-4 background and our ILBs suffered for that. You can blame Chan for keeping him, or you can applaud Chan for giving him a shot. Sometimes things work out, other times they don't. Cross will land on his feeet and will most likely appreciate that Chan gave him a shot.
The bigger concern is Edwards, not Cross. Edwards has never been a DC before. His sphere of influence with position coaches may be limited because of that. Chan's selection of Edwards is something that will be scrutinized throughout his tenure as HC. If Edwards turns out to be the next Buddy Ryan then Chan will be a genious. If Edwards is not adequate then Chan is open for second guessing. I suspect that Chan will give Edwards another year.