Can I give someone stake/equity/shares or similar for a project in the company without giving that person any equity in the company?
If not, has anyone found ways to accomplish something similar?
This is for FL based company.
What are you trying to achieve? This easiest way would be to setup a revenue-sharing deal. Person X gets 30% of all sales of the product for the next 2 years. That's as close as equity without getting into legal trouble. This is standard for sales people, but you can use the same structure for key contributors. Just don't abuse this and be very selective with who you bring onboard.
In the US you have several different kinds of business. You'll have to talk to an attorney about which one suits you best, and I'm not an attorney. But I'll summarize for you my understanding of what may be practical for you. I'm assuming that you're capable of doing the proper accounting.
You'll have to talk to a lawyer (and a tax adviser) about which option is the most suitable for your specific needs, but to me it looks like a partnership or LLC would be the easiest to achieve what you want. For C-Corp - you'll have to give some equity.
You should, of course, have the agreement be drafted by an attorney and ensure proper representation for everyone to avoid later claims of invalidation/duress/fraud.