I was getting something similar when playing a b231/b238 build with the b240 update. Most of the sleepers were spawning in as wolves. A fresh start fixed it.
I have found the occasional silver/gold vein (typically only a couple blocks in size) while mining for oil shale in the sandy biomes. I got really lucky with one of my A16 playthroughs and got a vein that netted me over 100 gold and ~60 silver. No more machete blade-selling in that one!
Pretty much. The previewer is a bit more high-resolution than a16, so it will take a bit longer to load. Make note of the region in the previewer if you plan on using the seed for your next game. Astora seems to be a pretty balanced one for this stage of experimental (with a nice slew of traders...
They are no longer lootable. They will drop a bag if they had loot when you killed them.
Normally, I ignore the release notes for updates, but this build has changed a lot of things.