I would start be getting the SPL Deverb plugin and it is only $29 right now too. I would see how the sound from the camera mics end up after using this. It is not too much of an expense and it will come in handy for other things I am sure.
 
https://plugin-alliance.com/en/checkout.html
 
Here is some info on it too:
 
http://spl.info/produkte/...icroplugs/de-verb.html
 
If it does reduce the ambience on the camera mics then you could try using EQ to improve clarity.