Definitely need early war French and Austrian cavalries. That's at least six sets right there, maybe more if you want to do things like mounted MG sections for each as separate units.
As for Jaeger zu Pferde, you can use Strelets German cuirassiers since helmets at this scale are pretty much indistinguishable. Oddly enough there is no Strelets set of plain old German dragoons for the early war period when they would be more useful than the late war guys. The most realistic use for those charging late war dragoons would in post-war urban combat against The Spartacists or other German Reds.