Lots Of Error Questions

Was recently going through a book of pennys that a family friend sent me about a decage ago, and in the back there were examples of different types of error coins and there are some that I am having a hard time identifying.




Firstly I have a coin that appears to have had another planchet over top of it while it was pressed, I am pretty sure this occured in the mint because the reverse of it looks perfectly fine. I there a name for this error?




This is labeled as a potientual extreme lamination error. To me this just looks like somone took to it with a screw driver but ive also seen mint errors 10 times as hellish as this so an opinion on this would be nice.




On this penny there appears to be some kind of bubble around the rim. Never really seen this before so a name for this would also be nice.




Here the "VDB" on licons sleve appears to be missing. Dont think its valuable but possibly some kind of blockage on the die?




Same as the last one exept the "FG" is missing.




Here are 2 pennys with weak strikes on them, Dont think they are valuable but some info on how this happens would be cool.




Lastly I have a pennt that appears to be brass. I know that the mint has confirmed that occasionally a zinc planchet would get stuck in the copper baths and would dissolve which would plate the following pennys in bass instead of copper. I also know that this is a common high school chemestry expirement. My main question is, Is there a way to tell the difference between a chem experement and an actual mint error? and would an actual mint error be valuable?

I know that is a lot and even if you can only answer one of my questions it would still be greatly appreciated.