Is a lease valid if my guarantor hasn’t signed? what are my options for getting out of this situation?

Yesterday me and my two friends went to, what we now is a slumlords penthouse to sign our new lease. The lease required our two guarantors to sign the lease digitally, but they however declined to do so because the lease terms were not agreeable.

The landlord was using a discount clause to charge different amounts for the first 8 months and last 4 months of the first year, and then essentially coerced us into signing a work contract for the last 4 months to “make up for the difference”.

The lease certainly has all 3 of our signatures, but none of the guarantors, and without their backing we cannot go forward with the lease, but the landlord refuses to back down because just our 3 signatures are enough. Is this accurate, or are we in the right for believing that until the guarantors signed the lease wouldn’t be valid? He is currently arguing that if he can’t find someone to take over before our term starts then our last month deposit could be held liable to costs.