Over polishing can happen/doe happen on any die. It is a common die event. It is used to extend the life of a die by rescuing an issue that happened. To me a polished die add no premium. Others go nut so over them. The weakened roof lines can happen on any of the Memorial cent years. So the obverse will tell you what year your coin is.
I imagine the OP is referring to the second pillar/column on the monument at the left at the top of the pillar there is a gap where it does not connect to the roof. The first photo looks like a possible Struck Through Grease. The second photo looks like it may have taken a hit. I'm no USA coin expert but the second column is the The only error possibly I see.