Creating a biome, the features page doesn't actually spawn those features except for the flowers and tree's only

So far from what I have tested anyway is when I make a biome using just minecraft's sand or other blocks(tested multiple), and try to do custom trees, only these things work. 

Custom Trees: Yes unless it's cactus

Trees per chunk: Yes unless it's cactus

Seagrass: Yes

Vanilla Flowers: Yes

Mushroms big/small: Haven't tested

Sand Patches: No, they aren't working

Gravel Patches: No, they aren't working

Reeds per chunk: Nope 

Cacti per chunk: Nope

So if anyone has a good workaround in meantime, I'd appreciate it. 

Mcreator Version: 1.16.5(2021.2)