Window Installation Concerns

I purchased three new windows from one of the large home improvement stores and had them arrange the install. The contractor who came out to do the work did not seem to really know what he was doing and the work looks shoddy to me but I'm getting push back from the store. Since I'm not a professional, I don't really know if the install is "fine" functionally and just looks amateurish or if it was done poorly and I should insist on a redo. Some of the things that bothered me:

1. The windows were not ordered with brickmould (mistake on the part of the store). The installer said he could make it work rather than have them order proper windows. The installer cut out the old window and left part of the original brickmould. He put the window in and the window edge and the old brickmould were flush, no overlaps anywhere. At one point I looked from the outside and there was a 1/4" space between the window and brickmould and I could see inside the wall to the spray foam insulation. He filled these gaps around the window with silicone.

2. When I complained to the store that I didn't think that this was a satisfactory way to seal them, they sent him out to make vinyl brickmoulds. These are essentially four pieces of vinyl overlapped together like a frame. They are held to the exterior wall and window by silicone and the corner edges do not fit together, are not siliconed, and are unsealed. I'm concerned that water and air are going to get in over time as the silicone weathers and cracks.

My question is am I being paranoid? Is silicone a sufficient sealant that I should trust or am I looking at major problems a few years from now. Should I hire someone to come and give me a second opinion? Here in Calgary winters drop to -40 and I've heard that if not properly sealed and insulated, I will get moisture build up and ice in my walls.