scenario 1( first job has already completed input of “start phase” only thing left is the “progress and Complete phase” can i edit the form for the subsequent site to begin the “start phase”?.

- Yes, in this case, the workers are site only have to select from within the “progress and complete” section of the form , select the name of the job they are updating and then update with evidence.

scenario 2, i accidentally edited the Google Form, in the section i wasnt supposed to, but i have replaced it with an exact replica, will it work.

- Short answer, NO. The automation is broken, you will have to re-purchase the subscription and redo the one time setup again. There is no way back from this.