Any word on when the Chimera, or any Imperial SD's really, will be reprinted?

The Chimera reprints are done and currently "On the Boat"

https://www.fantasyflightgames.com/en/upcoming/

This means it takes about 1-2 months to hit the shops.

ISDI/2 pack has been rare for most of this year and may take until 2020 to be available but they show up on eBay from time to time.