How many impressions can you get out of each mask before it has to be discarded? Last time I heard about this tech, that was the limiting factor.

This uses e-beams to make the mask, right? Edit: here's their research paper (7 years old but note the identical model name FPA-1200NZ2C):

http://cnt.canon.com/wp-content/uploads/2016/08/Nanoimprint-...

Turns out they e-beam a "master mask" and then use that as an imprint to create "replica masks". Then the "replica masks" imprint the wafers. Sadly you still have to start with a crazy-expensive e-beam mask.