Having run a very successful local campaign fighting a similarly large multi national company including taking Stockport council to court, winning, stopping the development then going national including being in every paper and TV station you can imagine, I agree with Duke... Campaigns can be run very cheaply at a negligible cost and I'm surprised you are considering "treasurers" at this point! Certainly you don't need charity status and would be unlikely to get it anyway.
A word of warning... based on sadly too much experience ...even with massive support if you ask for donations its unlikely you will get much.. especially considering the financial situation at mo... Do what we did.. presume you ll get nothing, do everything on the cheap by begging and borrowing and recycling, then every bit that does come in is a bonus.