A picture is worth a thousand words, so:

Also, the spawner hidden in the 'basement' doesn't seem to have been created correctly as it spawns pigs.

yea it needs a lot of help lol, a trap at the top also seems to malfunction...
I'll look into it soon, will probably just give up on using datapacks and go back to hardcoding it...

Ran into one of these right by my spawn in a new world and without the traps or any mobs I immediately felt like I was cheating. Just had buckets of gold and fantastic OP loot with no risk on my part.

mostly fixed in pre release, I'll make a new issue for lack of trap at the top