Opinion-based articles/posts are referred to as editorials in print. You might be able to use that when dividing things up into categories.
You can say whatever you want--just be prepared to accept the consequences of what you're saying. Personally, I would keep you any personally identifiable information or images off the site (names, birthdays, photos of familty, employment/employer details, etc.)
As for trolls and whatnot, you can send all comments to a moderation queue first before publishing them and set up spam filtering. For the most part, people who are posting these extreme negative comments do so behind the veil of anonymity and really can't do much more than stir the pot to try to get a reaction.