I'm a dilettante at RPG Maker VX Ace, but it sounds like you're walking blind into several potential problems. I don't mean to be discouraging, but you should give them some consideration, similar to the issues Cazador raises.
To answer your major question, the Game.rgss3a file that contains all of the game text apart from the map images is encrypted, and the text strings are not stored in ANSI in the binary, so you can't just go and overwrite the English text in the game files. You're going to have to work with the unencrypted project, and that means all of the "source control" problems Cazador describes.
My first question would be if RPG Maker VX Ace even supports Unicode Cyrillic. Since the engine is itself an English localized version of a Japanese original, my first guess would be "yes", but if it doesn't, you're probably shit out of luck. You might be able to work around the problem with a Cyrillic font overlaying underlying ANSI/ASCII strings if a one to one equivalency can be achieved, but that's a good way to guarantee a lot of spelling errors. The *.rvdata2" files that constitute the "source" of the game's project use ANSI/ASCII strings in their binary, so...
I'd secondly reiterate the difficulty of translation mentioned by Fulminato. Doing the job well requires a mastery of both languages.
Thirdly, crowdsourcing the job to multiple people is a good way to ensure poor quality, unless there's an editor enforcing standardization. At the minimum, you want to establish a set of standard transliterations of names of all PCs and NPCs, otherwise individual translators will use their own discretion and create a confusing mess.