You have a difficult problem mainly because of the shark. For the rest..
I would suggest a hypo treatment in a separate qt
tank or I believe these animals (with the exception of the shark) can handle cupramine. If you use cupramine, use a full dose. A half dose will do nothing to kill the parasite.
Now to get the main tank clear of the parasite, a fishless period of 6 weeks in needed. Copper will kill the shark and I have not seen any data on the effects of hypo on sharks. Since they generally are pretty resistant of ich, he would need to go in a separate tank for the duration of the fallow period. I would not leave him in the main, even though sharks are resistant, they can still allow the parasite to survive.
Another possibility... Does you tank contain any LR
, inverts (doubt it with this crowd) or corals?
If not I was thinking that maybe you could treat the main with hypo and isolate the shark in another system. Like I said, not sure if the shark can tolerate a hypo treatment on not. If it is a true FO
system, this might be your easiest option.
Perhaps steve-s will chime in about the shark situation.