Poor little guy ((HUG))
First if you cannot find one remedy to cover all the symptoms I would start with the most urgent or troublesome. you know your child's symptoms best, and may decided the green mucus should be treated before the ringworm.
Something like Ring worm you might be better off getting a professional to help. But if you are going to try it alone then I would suggest doing one remedy at a time, so as to not confuse the body. Some remedies can counteract others.
Some guidlines that we follow for taking remedies. the less severe the problem the lower the dose can be. 30 would problemly be better for ringworms.
You should/can give the remedy every 30 mins till you see a reaction (improvement in symptoms), then STOP. The guidlines on the bottles are there because they HAVE to put them, but not always the best way to use it. If after 12 hrs you do not see a difference you have the wrong remedy. I treated ds for worms and only had to give 3 doses.
If symptoms return you can redose.
I would still stick to the same quanity with 6 as 30.
Once the ring worms are gone you can start treating the other things. You should be able to find one remedy that covers the teething and congestion, instead of using two different ones.
As well this site is great for helping to find a remedy:http://www.abchomeopathy.com/go.php
You may also want to look into some herbs to help treat other things while on the first remedy.
For example, increasing vit C, acidophilus(sp?), and garlic caps, will help boost his immunity and fight an infection (green mucus)
As well, making a tea of say fenugreek would help with the congestion (it's a mucus inhibitor).
Just don't use things with strong odors (like peppermint) as they can stop the remedy from working.