First, I'd like to commend your interest in attempting to create some community involvement. I hope it goes over well. Community is something I feel like this site needs more of, and not just for "the in-crowd". Everyone should feel welcome.
Next, I will say that I have absolutely no inhibitions about reporting inappropriate behavior to administrative staff. Have your opinion, please. Voice it. But do it in a way which is respectful, non-confrontational and productive. I would like to see this conversation serve its intended purpose, not get shut down for peacocking and posturing.
As for the topic, this is one subject I've had lots of experience with over the years. It can be difficult to know how to handle NPCs. The topic is subjective, and can vary from situation to situation. In many cases, it really depends on the style of roleplay management the GM wishes to employ.
In my experience, Non-Player Character is a term which only means that the character is not assigned to a player. It does not necessarily mean that the character is unimportant, or is free for use by the players. I tend to restrict access to NPCs by players, because it is too easy for a player to "win" a conflict if he has full rights to post reactions from his opponent.
NPCs in my roleplays tend to be completely off-limits to players, unless specifically stated. Even then, it is situational. There are minor and major NPCs, but in every case I treat them as separate entities, with their own rights and backgrounds. The conflict of interest is just too great a temptation in my eyes. A player posting a reaction from an NPC he's fighting is (in my opinion) no different from posting a reaction on behalf of another player's character. I see it as just the same.
I also believe in minimizing the involvement of NPCs in a roleplay. Too many of my roleplays ended up fizzling because I had too many NPCs helping the party. Nobody wants to play second fiddle to a character that isn't even a real member of the party. Even less do players want to be "saved" by NPCs. These days I tend to only employ an NPC where necessary or warranted, despite my great love of creating them.
In short, they are a valuable tool, but are easily misused (or overused). It can be difficult to know when to employ them, but if you figure it out, an NPC can make the difference between a successful roleplay and a dead one.