I think even other Chee were raising their proverbial eyebrows at Erek and saying "And just what are you going to actually do, being nonviolent and all?" at least that was the impression I got in book 10, but since from the moment we meet the Chee they already have a plan to stop being nonviolent it's possible that up to a certain point their infiltration was nothing more than an attempt to see whether or not the best interests of dogs would be upheld under Yeerk rule.
But I think they could have gone around sabatoging engines and weapon systems to slow down Yeerk efficiency, or disable cloaking devices like the Animorphs planned to in order to alert mankind to the danger without violating their program, I don't think their nonviolence extends to accidental deaths, I mean if I recall correctly in the last book ... [spoiler]Erek disabled the pool ship's weapons which nearly got them all vaped and didn't bat an eyelash, infact was waiting for Jake to apologize to him.[/spoiler] ... but it's been a while since I read that book, I may be recalling wrong.
As per the topic, honestly I think Erek and co were more interested in playing with dogs, human games might not have been to their interest.