The floating mineshaft is caused by MC-105035, and the strongholds have always generated like that. This means that this may also relate to MC-70705, which shows (intentionally) glitchy stronghold generation underground.
Village homes are spawning two blocks two low--i.e., their jigsaw block needs to be two blocks higher. Not sure if they even want to keep these things down near level 0 in the game.
The floating mineshaft is caused by MC-105035, and the strongholds have always generated like that. This means that this may also relate to MC-70705, which shows (intentionally) glitchy stronghold generation underground.