Those blocks feel somewhat unfinished.
1) inverted_question_block.asm doesn't have proper description (<description>)
2) !blocktogenerate in inverted_question_block.asm and inverted_question_block_anyspr.asm have unfinished commenting.
"16 - used", but used what? (Used block)
I'm not sure what 19 and 1A mean (cage), they're related with nets.
1B is completely blank (1B - ), it's related with switch palace switch.
3) This block doesn't spawns sprites exactly underneath it, but rather inside, which can lead to some sprites interacting with player through it (so far I noticed this with mushroom and chucks)
Edit: 4) You don't trigger blocks when standing on it's top corners.
This definitely a creative idea for a block which could be used in quite a lot of places. You could have made it a little more user friendly, at least by adding more defines.
During the moderation, I added the sa-1 tag since the blocks themselves are actually SA-1 hybrids and I included an SA-1 compatible version of GPS's spawn_item_sprite routine. I added assertions to the Map16 variants of the block to make them impossible to insert without first patching the Bounce Block Unrestrictor patch.