1), Yes, your symptoms are indeed indicative of possible mercury poisoning. The fact you have 16 amalgams makes that probable. That is a large amount, even by mainstream dental standards. I'm amazed you're still up and about at all!

2), Start with diet in my opinion. Exclude all sugar, wheat/gluten and yeast products for a start. Keep fluid intake simple with water and herbal teas (black tea maybe ok too). I would advise some homeopathic drainage support to help the liver/kidneys with the toxic overload. If possible, see if you can get hold of a binding product like "algin" to help with binding up some of the toxins/metals at the sametime.

5. One thing at a time and step by step with removing sources of toxins from the mouth. I would certainly look at getting the root canals removed at some point, unless they have been done properly by a biologic dentist with proper biologic materials and are non toxic.

6. Vitamin C (powder form with bioflavanoids is best), vitamin E, essential fatty acids from fish oil (mercury free). Zinc, magnesium, B complex, milk thistle. (take vitamin C, magnesium, milk thistle, B complex 3-4 times daily as they are used up by the body pretty quickly and you get much more out of them when you take them more often over the course of the day. You can split up the dose if you need to The others can be taken once or twice. Selenium only if you can tolerate it. And make sure you have enough iodine in your diet, or add "some" supplementation. Mercury uses up/blocks, displaces alot of these elements.

I cannot readily answer the other questions and I hope somebody else can for you.

Please don't overwhelm yourself. You are likely too toxic to cope or take much in anyway as you have stated and I relate to this. I started with diet alone, even with a mouth full of amalgam and that made a pretty big difference in a few weeks and lessened my toxicity and got me stronger, then I went further with other products. So start with something like this and take some of the load from your alraeady toxic body and see how it goes. You may need to reduce fruits and other high carb intake too if you have a really bad candida problem going on. Buut I would definitely advise eliminating sugar/yeast/wheat/gluten products at the minimim.