Is there a ceiling limit on net gain for non-profit organizations? Will making a profit nullify the non-profit status?
No. The only thing that non-profit entities need to watch out for is the earning of taxable business income (rents and advertising profits, for example). The earning of such income will not of itself destroy the tax exemption status of a parish, but it will require the filing of a tax return - the form 990-T.
What does it mean "not affiliated with any political agenda?"
To retain tax exempt status, IRS regulations state that the parish may not engage in any political campaign on behalf of or in opposition to any candidate for public office.