We cannot offer legal advice; however, the Preparation and Award Checklist in the User Guide and our Contract Considerations videos might help you interpret the documents and processes.
The User Guide (10.3.2.1, 10.3.2.2) suggests that Owner caused delays (per GC13.1) entitle the Contractor to reimbursement for costs and lost time. In this case, the CA must act impartially and issue a Change Order for the proven impact, even if the CA was the cause of the delay.
Sorry, there are no MMCD templates for subcontractors.
The Contract Considerations Video, "Partial vs. Staged Substantial Performance" should provide the answer.