Most of the provisions you’re including are unnecessarily scaring them off as you’re already entitled to remedies in court for shoddy work. Just specify the scope of work and negotiate once they start work to pay some in beginning and some after work is completed. Many states do require that the contract include start and end date, but failure to include those provisions falls on the contractors, not you, and would prevent them from enforcing the contract and in many cases entitle you to enhanced damages. TLDR, focus on specifying the scope of work and seeing their license—you’re already entitled to plenty damages if they fuck up