I think I remember reading that only official plugins are allowed.
yes, using plugins that did not come with construct instalation will not let you upload your game to arcade.
I think it's agreed most people should never adjust official plugins for fear of ruining the plugin I seem to remember you know your way around the SDK. Would it work to open up my updated plugin and cut out the reference for user token and plug it into your official plugin?
adjusting official plugin and uploading the game to arcade will let you upload the game, but will break it, as in the arcade plugins are in their original form, not the uploaded one, so the game will work locally with modified original plugin, but will not after it's uploaded.
also this is not the main problem, main problem is that both official plugins (dictionary and facebook) are lacking some basic and very needed functionalities. also the facebook plugin uses app secret to post scores, which is a very bad idea, as application secret should NEVER be used nor it souldn't be available client side (which javascript is) so actually every game that uses the score posting of the official facebook plugin is wide open to hacking it.