Is it legal, in any way, to pay an individual (unlicensed) for bringing a lead (in New York State)?

Options:
1) Developer with an unlisted property pays a individual who brings a buyer a flat finders fee ("thank your friend")

2) Developer pays a broker for closing the deal with the buyer AND pays individual a finders fee for bringing a buyer (pays the individual who brought the contact info to the broker)

3) Developer pays a company a marketing fee once a property is sold, company pays individual a finders fee for finding a buyer

4) Developer pays a company a fixed fee for marketing (whether sold or not) company pays a individual a finders fee for finding a buyer

I've read through some law, and called a few lawyers - most seem to only say "no", seemingly more so out of fear than any specific research or cited law. I'd like to read the reason why for each of the above, if it is know to you, so that I can be sure to avoid and potential pitfalls.

Please let me know if you've worked out a way to pay a "friend" for their service in bringing a buyer to a developer/owner.

Any links you can share, or forums/forum posts would be helpful!

I understand buying leads, presumably in bulk, is legal. I'm trying to understand where the boundaries stop.

If someone provides a contact, and that contact turns into a sale, who can compensate that someone and on what grounds (what is the process). Looking for developer->friend, or developer->agent->friend.

thanks