In this one,
the building is leaning, and his ear looks too large. 50 mm is not generally considered short, but it is a bit too short for most portraits and if the camera is not level front to back, keystoning happens. I’m impressed the little guy is up, dressed and outside at 5:30 in the morning. You must have been going for the golden hour. Noise is apparent. If you open the JPEG to full size, there are all these bright little dots. You could have shot at ISO 400 by halving shutter speed and opening the lens to f/2. I’m assuming you were using Canon’s 50 mm f/1.8 II lens. That would give a narrower DOF but a cleaner image. The other thing I notice is the drain pipe growing from his head. Look around the frame to see what is there besides your subject. Sometimes you can move or change the angle, and for those times you cannot, there is Photoshop.
The covered bridge
is a really cool structure. The photo is about 80% there. If this started as a raw file, you could easily recover the trees outside. Other options are to shoot 2 exposures and merge them, or flash. I don’t think flash is the best option in this situation because of how fast light falls off, and how close you are to the structure. It would be very bright by the camera and may not reach the length of the bridge. Two exposures would work if you used a tripod, but then you have to carry it, or find something to use as a tripod. This is the sort of shot where the power of a raw file really shines. It’s too bad the scene outside is completely burned out. At 18 mm, you can easily get away with 1/25th to stop most motion, that would let you drop ISO to 400, while keeping f/7.1. I think f/7.1 worked well for you. Lots of depth.