-Chlorella mobilizes as well as binds to mercury, so no you do not want to use it with amalgams still in.
-Algin just binds, so you can use it anytime.
-I agree with your dr. The synthetic chelators are more agressive and also bind to necessary minerals. This can make you very sick.
-Eggs are sulfur containing which I believe mobilizes hg so I think it depends on how sick you are now and how much mobilized hg you can handle.

Hope this is helpful