Salesforce custom object configuration

I have three custom objects, two of which are already created but have no workflow rules or Process Builder automation yet. CustomObject1 has multiple records from CustomObject2 and can be seen in a related list on CustomObject1. Here are my requirements: 1. Only one CustomObject2 record can be in an "In Progress" status at a time on a CustomObject1 record. The first record will be automatically created with the CustomObject1 record is created. 2. As each CustomObject2 record is set to status "Completed" the next record is create in an "In Progress" status based off of a sequence which should be contained in CustomObject3. The sequence will continue for five or six steps or until a record is marked "Cancelled". 3. If one of the CustomObject2 records is set to "Cancelled" the process should stop and the CustomObject1 status should be set to "Cancelled" and custom field for "end date" should be populated. 4. The name of each step in CustomObject2 is a certain "function". I should be able to change the name of the function in CustomObject3 or reduce the number of steps in the sequence, therefore updating the name of the function on CustomObject1 and updating the number of steps in the process. 5. A custom field called "Current Function" on CustomObject1 should reflect the "In Progress" step/function of the CustomObject2 record currently open so that I can look at a related list of the CustomObject1 record and know which step/function it is on without opening the record. 6. When the final step/function outlined in CustomObject3 is marked "Completed" the "end date" field is populated and the related CustomObject1 status is set to "Completed" and the "end date" populated as well. I need to be able to speak to and screenshare with the developer who is hired to help complete these configurations for better clarity. The developer needs to be willing to accept modifications to the requirements based on the limitations of Salesforce and for ease of completing the project.