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.
EDIT:
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?)