Ossian Studio's Alan Miranda comments on the effects of the Atari events on Mysteries of Westgate and explains the usage of MoW with the toolset.
The news post about Atari's CEO stepping down and pulling back on internal development does not affect MoW or NWN2 for that matter. Those issues are with Atari Inc. Keep in mind that there is a difference between Atari Inc. and Atari Interactive Inc. (check out wikipedia for more details). Anyhow, we developed MoW internally at Ossian, so this wouldn't have been affected regardless.
He also explains the usage of MoW with the toolset.
As for an exact release date, there are always a number of factors to consider. We'll let you know when we have a more firm date.
The areas from MoW wouldn't be available to use elsewhere (i.e., opening MoW up in the toolset and exporting them as erfs). The BioWare premium mods were encrypted, if that's any indication. Other more easily distributable content from the game would be made available to the community, which is what both Ossian and Atari would like to do.