For cracks in sheeting (like your first pic), if you can get it level, just hit it with a couple drops of thin CA. The CA will wick along the crack and glue it together.

You can buy "light spackle" at Home Depot or Lowe's. This stuff will fill small dents and sands very easily. (I prefer it to microballoons and epoxy, which can be very hard to sand smooth, especially on sheeting.)

Looking like a good repair job so far!
Dennis-