The use of the speaker stands was ingenious. I'm surprised you managed to get the post out of the concrete given the snow in the previous photos. Posts in Ontario have to be 3 or 4 feet below ground level to get below the frost line but I guess that's not an issue in your area.
I've been through one bad build when we put the addition on. Contractor was a client of the mortgage firm I work at so we wanted to give him some business. He was good on small jobs but the addition was way over his head. The concrete forms didn't stay locked in place for the basement walls so one wall was considerably thicker at one end than the other. Had to correct that with internal framing. It was poured just before winter and we had to get bails of hay from my father-in-law to keep the footings from freezing in winter until construction could resume.
When they framed the main floor walls, several studs were not nailed in properly through the sheathing and you could move them side to side for lack of nails. The roof trusses were a little too long so one of the workers thought he could simply trim them down with a skill saw along the entire length. Had to reinforce them afterwards. When the roofers failed to properly install an underlay and ice shield around the roof perimeter I had enough and fired him. At least the addition was house-wrapped, shingled and basement floor poured by then. I ended up finishing everything else myself except for the exterior siding. That was done by a local farmer and his son working for a siding company off season. Nice guys and did a great job.
Very stressful reno as we completely reconfigured the house including the bathroom and kitchen and had to live at my parents until the plumbing was completed and the house was livable. Drove the inspector crazy that it took so long but the only deficiency notices I received for my own work were two incorrect drain connections and some extra nails on a ganged electrical box. I learned more about construction in those few months than any of those jokers will learn in a lifetime. At least the end result was good since the gaffs with the internal structure were fixable and not visible once the finish was up. Oh the joys of home renovating!