I thank you all for your constructive inputs. I've had a rather busy week-end and an even more busy week ahead, but I'll do my best to come back here and integrate some of your points into the Shaltszs background, but I need some more time to mull them over.
I'll probably have to expand on their first contacts, as you managed to convince me it'd have been hard for such a species to discover Warp drive by themselves.

In the meantime, don't hesitate to keep the good ideas coming