Well pointers I can't give - I have only just started really getting into modeling.
Suggestions:
I think sabers would work good with the British style cavalry. I think lances would work best with the Kaiser cavalry. Not sure about the French/Mon so much, sabers would be good - but I really liked the baguette design haha...
Also, I think a Cossack/Russian faction would be great - with fur caps. You could also do something Ottoman/Janissary style. Not to mention Austrians (same style as Kaiser?), Serbians, Italians and Americans. But I am sure you have thought it over and have it on a back-burner.
I hope to see more of your work released as you go, soon would be great - but I say take your time if you need to get it done right.
Lastly, will you do heroes? I think that would be awesome! Like Red Baron for Kaiser, Paul Baumer for Kaiser (All Quiet on Western Front)...Lord Flashheart and Captain Blackadder for the Sir Army.