The Airlinks are capped at 90 76 seat aircraft. With Mesaba and Compass both operating 36 frames for a total of 72, that means NWA can only allow the Airlinks to fly up to 18 more planes. While it would be nice if Mesaba got them, only NWA knows where they'll be operated. This assumes NWA even takes their options.
I don't think the reason we're operating 200s is for place holding of any sort. I think it's simply getting us back to operating at the size we were pre Ch11 and before they stopped the deliveries of the original order of 200s.