Rental agreements are completely different from roommate agreements. Rental agreements are about how much rent is to be paid by the tenant (your prospective "roommate") to the landlord (you). Roommate agreements are about who does what (e.g., household chores, meal preparation etc.) during the term of the rental agreement.

Your condo by-laws allow you to have another person living in your condo with you, as long as you don't charge that person any rent. And (obviously) if you're not charging your roommate rent, you therefore cannot have a rental agreement. (No rent = no rental agreement.)

So if you want to have a tenant (i.e., someone who pays rent to you) in your condo, a roommate agreement will not cover the situation. You will also be liable for any penalties (fines, liens, etc.) that the condo board applies to you for breaking the condo by-laws.

Finally, yes the condo by-laws are binding and enforceable. You agreed to them when you bought the condo.