Noticed a lot of world generation issues in this snapshot (18w09a). Villages are especially messed up. Often generating with trees in them overwriting parts and other placement issues. Then there's the one pictured below...note the wrong blocks being used for the well and the rest of the place is just a mess.
18w09a Snapshot
Seed: 27829440020180844
XYZ: 181,75,102
Pic 3 & 6 show the town well...cobble is replaced by grass_block, fence is replaced by grass, water is replaced by grass_path.
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Please attach the world here.

Had to spit it up to get it by the 10MB limit. Sorry I don't have any online storage I could upload and link too.
I'd also like to note that since I'd been playing the world and have changed the village some since I reported this issue, I tried first to copy the the world so I could send an unaltered world file. This didn't work as the copies didn't have the corruption, so something is happening when I first gen a world that has either stopped or has another cause.
So, I like playing Hardcore SMP, which still doesn't delete the world file properly when you exit and you have to go into the 'select world' screen and delete from there. Because of that, this was the 5th world I'd made in about 2hrs of game play, having died & deleted the ones before with out restarting the client. Could it be that all the previous worlds could have caused the corruption in this one due to bad or incomplete trash collection on on the part of the JRE?
P.S.: I have also had issues where after dying and deleting the world the death screen from the previous world shows as the background on for the GUI on next world creation, this is what makes me think there might be an issue with JRE memory cleanup. I will get a screenshot the next time this happens and start a ticket on it.

I am also seeing fences attaching to air blocks in mineshafts. Picture attached.

The village is MC-125807, a bug where rarely block types are mixed up. Mineshafts and the other issues you described are tracked in separate tickets already. Thanks for the upload!