Villager Compatibility?

I was thinking that maybe users could add custom "addons" to villagers where you could either:

Create your own villager job: You can design a new texture for a villager, or maybe use a preset. You would be able to designate any block as a villager job block, such as bedrock or a bookshelf. You would be able to  set a sort of "loot table" for the villager job where you can choose tradeable items (ex: 10-14 emeralds for 1-3 diamonds, you can have random ranges too).

OR

Edit a pre existing villager loot table: You can still do the above, but this would be another option. This option would allow you to change a loot table of a pre-existing villager (maybe add a way to easily change modded villagers too through the code) although it wouldn't bring up the loot table already existing, because that would probably cause too many problems (maybe a way to import loot tables instead?) so you can start redoing the loot table from scratch.

Thanks for reading!