While I don't agree that "we all do it" those small traffic violations are not a deal breaker.

That means that is would violate their contract if you went behind their agent's back and negotiated directly with the seller.

Make a copy of it and highlight every violation to date, for emphasis, and address each one.

Not disclosing the option price to an appraiser also will be a lending violation, failure to disclose an option price paid is also a violation of ALTA requirements and the settlement agent will fail to properly account for settlements.  

Otherwise YOU are in violation.

If assignment is prohibited major title companies will not allow the use of the end-buyers funds to be used for your purchase because assignment violates terms of the contract. 

That would just be another violation of the lease.

In my attorney's opinion, this is not grey and violates SEC regulations.  

your 2nd q is a tuffee, i'd stay away from houses that are zoning is being violated. 

After all, fees is how property managers get paid, and not just the fees they charge you to manage the property but fees paid for various violations by the tenant is the other revenue stream for property managers.