I can confirm terrawart only drops terrawarts, the normal consumable one. It doesnt heal hunger or add an effect.
It has no special growing conditions, but the one i put down has 3 layers of dirt under it for max effect.
It also grows very slowly.
I can also say terra wart looks identical to nether wart in its first stage, but its 2nd stage it goes blue and 3rd stage ready for harvesting.
Since instead of double posting, I just got a really strange anomily with a friend. We was breeding crops, and a combo of a pumpkin+stickreed got a coffee. I thought it worked as the 2 tiers combined to get a tier of the total, or less. But stickreed IV and pumpkin I got tier V.. So how did it get a tier VII (coffee?)