My son signed a lease that required 2 guarantors. The lease lists all 3 parties names, but only 1 guarantor signed the lease. When I signed the lease as 1 of the guarantors I was told I would get a copy of the lease when the other guarantor signed it. The other guarantor never signed the lease and I never got a copy of the lease. Is this lease legally binding if all parties did not sign the lease and I never got a copy of the lease?

The lease is still legally binding, but only binding on the people who actually signed it. So now you are the only guarantor for that lease. The fact that they didn't provide you with a copy does not prevent it from being legally binding. You need to send them a letter demanding a copy of the lease.