If all of these supplements give you dosages for an adult human, you will need to titrate the amount down alot for a 6 pound cat. So if you assume an adult human that weighs 150 lbs, you would then want to give the cat 1/25th of the amount recommended. The one supplement you mentioned for felines should have a dosing schedule on it...I would hope. The vitamins you mentioned will not be in the correct ratio for a cat, but it will be better than nothing.
I like the idea of talking to the animal communicator for what is best for your kitty.