About your tetras:
I think since you said your tank is heavily planted, you can probably fit a pretty decent number of small fish in there. Obviously you shouldn't add them all at once, so just develop a flexible plan and see how it goes.
Most people would probably say my 30 gal. hex is pretty overstocked. It has 1 betta, 1 gold gourami, 5 ghost shrimp, 5 panda corys, 6 swords, and 7 rasboras. They all have their own space, though. The corys root all around the gravel. The shrimp stand on the plants or driftwood. The swords hang around the middle. The rasboras hang around the top. The betta and gourami wander around pretty slowly, and each have their own spots they like to sit. At times the tank actually looks really empty.
Your 29 gal. might end up being a little lopsided. If you've mostly just got tons of tetras, they might all be around the same area -- schools in thte upper/middle area who like to hide in your plants.
I'm certainly no expert, though.
About the gourami:
Even just looking at them in the store, I got the idea pretty quickly that they pick on each other but mostly leave other fish alone.
When I put 7 rasboras in my tank, the gourami chased them around a bit for the first two days I had them in there, but I never saw him do any damage. Someone also ate a lot of the tail off one of my panda corys, but I'm not sure if that was the gourami.
It really seems like my gold gourami is only aggressive towards other gouramis and fish he doesn't know well. Of course, I'm sure there are gouramis that have totally different personalities.