1. Cast iron plant (not sure) 2. Monstera deliciosa 3. Philodendron Selloum 4. Plumeria 5 and 6 I have not idea

When you sowed the seed, you might have seen the seed. Gooseberry seeds are small. I haven't seen bilimbi fruit in real. But it looks like the fruit is bigger than gooseberry. Seed might be bigger too. if the seed is smaller than cherry seed, it might be gooseberry.

Lots of things to consider. Where are you located? What state? Location has a lot to do with what you should and/or could plant. Stone fruit is usually advised to plant in full sun with good air circulation. Many even prune their trees open centered or vase shape to let more sun in and air flows better. Thus, growing stone fruit as a hedge may not be a good idea. Also, you need to think long-term, those tiny sticks can grow tall, far and wide. Planting only 1 ft from a fence will force you to consider a certain way of pruning it. A plum can put out 3-4 ft branches in all directions in a growing season. Let's start with what state do you live in?

I'm selling some seedlings online check them out: http://www.ebay.it/sch/nearestheaven/m.html?_nkw=&_armrs=1&_ipg=&_from=