My perspective is:
a) it would be desirable, though not essential, before proceeding to reconnect the switches in order to demonstrate that the lights are in fact functioning.
b) it would be desirable to have the trim which will fit into the plastered dry-wall on site, and to test the enlargement of the dry-wall plaster cuts one at a time by installing the trim sequentially as one proceeds.
c) I acknowledge there will be additional clean-up, but this should not be a problem prior to the installation of the finished floor or the floor finish
d) assuming, as I expect they will be, Mr. Barros' hourly charges are moderate, I would not hesitate, to pay him additional sums for the dry-wall-plaster enlargement and for the installation of the trim, (which is in fact a task for the electrician)
e) assuming, as I expect they will be, Mr. Barros' hourly charges are moderate, we expect to be paying him additionally for receiving i) the spiral stairs, ii) the inside doors, iii) the flooring materials, iv) the finish carpentry wood, and for painting and/or applying polyurethane to i) the spiral stairs, ii) the windows, iii) the inside doors iv) the finished carpentry, v) the  bulkhead, and or vi) the outside trim.

Because of his limited intelligence and the complexity of the projects he undertakes, I consider Mr. Barros vulnerable. So long as he continues to act in good faith, I am quite prepared to compensate him with both approval and money.

Please don't be offended by the baroque prolixity of my prose. I want you to be well, and as happy as possible, and I will endorse whatever you decide.