I'm not familiar with Canadian law, but an NDA can be signed between two individuals. The problem comes to how the specific NDA is written and what resources / IP it covers. If you sign with multiple people, those are just agreements between you personally and each of them personally, so getting them together in a room is going to be harder to "prove" / "cover".
I'd do yourself a favor and just have an LLC on hand for holdings. You can always transfer the property to other companies as you work out the details later.
IANAL, but this would make me personally more comfortable. It might make you look more official, as you'd have a company and theoretically more resources to go after an individual later.