Q: "Can I do video interviews of people or ask them to write on my site without compensating them?"
R: Sure. You need a written agreement however. Ask your own intellectual property attorney to draft the agreements [one for those who appear in the videos and one for those who agree to have their writings published on your website]. Good luck.
The above is general information ONLY and is not legal advice, does not form an attorney-client relationship, and should NOT be relied upon to take or refrain from taking any action. I am not your attorney. You should seek the advice of competent counsel before taking any action related to your inquiry.
Yes, Mr. Ballard already said it best.... get an IP attorney to draft an agreement. You need your company to own all IP rights in the interviews and contributions.
Q:"Can I do video interviews of people or ask them to write on my site without compensating them?"
A: YES. However, you need a copyright assignment agreement or to make them an employee. For what you describe, the assignment will be preferable.
Q:"What if my business grows and starts making a lot of money? Can those people sue?"
A: Anyone can sue, but there are sanctions if it is done frivolously.
Q:"If they sue, will they ever be able to receive more compensation than what their actual video or article made for the company?"
A: NO, if you have the proper agreements. YES, if you don't. That's why you need to see an IP attorney and get the right agreements done.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.