Wright is definatly playing prop during the game and if replaced him with Mateo we would disturb the structure alot more.
Mateo will prob come in off the bench after a week in wenty and would play similar minutes to Benny, then the week after I can see him starting in the backrow and playing aabout 60min at lock (similar to what Lowrie is doing now).
KK will be much the same IMO, prob start from the bench (after a week in wenty) and replace Robson after about 30min (similar to how Kinga would replace MK after about 30min) and allow MK to play the 80min. If KK is not being productive or MK needs a rest Robson can just come back on.
That would be the best way to deal with the situation without changing too much structure. Also the current game plan of looking for second phase play would suit KK more than Robson game (KK is a very good supporting halfback) and allows Mortimer to go what he does best on the edges. This will also allow Hayne to play as a hole runner and not worry too much about the creative duties, he could chime in as a second 5-8 as he sees fit.