Killing pests

Question
Hello,
I've just set-up my tank for two months and I'm facing several pests problems.
Firstly, there are worms; probably planarian. It's flat, has a pointy head and is white. Larger worms are pinkish at the middle. They occasionally come up to the soil surface to the glass walls.
Secondly, another worm, probably nematodes. It's thread-like and is white. Larger worms are reddish except for the tips. They also come to the soil surface occasionally to the glass walls and some swim in the water with the current as they do not have the strength to oppose it.
Thirdly, there are snails in my tank. I removed some of them but I think there are still some hiding as my plants seems to be eaten.
Lastly, there are bug like insects probably water fleas? I'm not too sure of this one. They are white and have a round body. Some of them have two round things below their body while others have one round( or sharp thing like a tail) below their body. I can't really remember as I've not seen them for some time probably being eaten up or they went hiding. I think the difference between these two is due to their gender?

Anyway, I want to remove all of them especially the snails since they are eating my plants but maybe not the water fleas as they seem harmless.
Regarding the worms, are they beneficial to the aquarium since they eat uneaten food? Would they like get into my body system and cause harm to me, my nerite snail or my fish? Different people have different answers regarding entering the human system as they aren't sure what type it is so I think it's best to remove the worms.

I have five rummy nose tetra from my previous tank but they don't seem interested in eating any of them though the water fleas seems to have disappeared completely(I'm not very sure) and the worms went into hiding under the soil but come out occasionally after I added the fishes into the tank. The worms are currently populating the part of the soil where water current is weaker. I'm not too sure where do the worms come from though. I'm suspecting from the plants or from the ADA Amazonia soil.

From other threads, they said to add salt mainly to shrink the worms but it doesn't kill them, does it? Or add garlic? Or add wafers to attract them then net them up; but I'm afraid this doesn't kill them completely.

So, my question is would the worms cause harm to me, my nerite snail or my fish?
Could the worms and snails come from the plants? But I've not had such a problem in my previous tank. They come from the same source but it has been about 4 years since I had ordered plants from them. Could they have come from the soil?
Is there anyway to kill them? Are the methods that I had read from other threads useful? If it would kill my nerite snail please tell me then I'll have her moved to another tank.
I don't feed my fish, am doing water changes weekly of about 50% and can't vacuum my gravel cause there are plants growing.
Thanks! :)

Answer
Arron,
the worms are there due to excessive organics and as you mentioned prob came in on the plants, same with the snails.
When you mention soil, do you have a peat, dirt, gravel mixture or just gravel?
You are also correct in that what will pretty much kill off the worms will also kill off the snail, and or snails.
To combat the worms, do some tank maintence, ie water changes and stir up what you can of the substrate to clean it up.
You may add a dojo loach, khulies, or clown loaches to eat up the worms and they will do that without destroying the rest of the tank.
I don;t believe anything in the tank can harm you so that is not an issue.
If you want to downsize the snail population put a piece of lettuce in the tank after lights out, later as the snails move to the lettuce to eat you can remove them.
Will that get rid of them all? no, but it will downsize the population to a manageable level and the loaches, dojo and clown will eat the baby snails.
You can also crush them against the glass and the fish will clean them up.
To recap, it seems you have alot of organic material in the tank, lowering that will clean it up as the available food for the worms will be reduced.
That along with natural means will help  you to get the tank cleaned up..
I don;t advocate adding chemicals to get rid of snails or whatever, always good to try the natural way....