Thanks for the multipliers, we're not leaving empty-handed at least ! However about blacklisting the entities of MineColonies I don't think it will affect the server, the limit is 50 NPCs spread over 100 000 blocks (Max colony size by default is 20x20 chunks, which is equel to 400 chunks so 102 400 blocks), even counting 500 constant entities for 10 players (unlikely to happen) it's only a drop in the ocean compared to the mob farms which are concentrated on a single chunk, but that's my personal opinion.
Also I'd like you to keep in mind that the colony is not loaded if no player is close, what I proposed as a first fix is only to make the NPCs work as long as a player is in range but more than 16 blocks away, since this is a bug that is not and will not be fixed by the devs (abandonned version). Fixing the bug is exactly what I proposed...
The whole colony doesn't work at the same time, but at least more than 1/50 can work with that fix.
But again, thanks though for what you've granted, it'll surely help a lot for building.