Machine Doubling is very common on the 1968-1972 cents. Even the big DDO of the 1969-S has a large percentage of them with Machine Doubling: Note on the yellow arrows, you can see the common areas MD is present on these coins.
Motto is showing die wear on the outside of the devices moving towards the rim direction. Not a doubled die, just die wear. You can see that on the motto devices in the last two images you posted.
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