Re: A combination to consider...
I think those sound fine. Try them and see what effect they have. I'd suggest taking the liquid mineral one in divided doses as the body can only absorb so much calcium at one time, and it may dump the excess which would be quite a waste of a good supplement.
I started with zinc picolinate, and had much success with that form. There has been studies that indicate concern with using the picolinate form of supplements, so I changed forms recently. But I found no problems over the course of one bottle's worth of use, so it shouldn't be a problem. Also, try to put at least 2 hours between your liquid supplement and your zinc. I'd suggest trying to take the zinc before your calcium dose as the calcium can interfere with zinc absorption. Calcium and potassium are okay together.
As to the 3500mg of potassium, I don't recommend trying to get all of it from supplements. Too much potassium can affect both the kidney's and the bladder. It is different for each person. I try to get 600-1200mg from the KCl salts, but sometimes I have to just up my bananas and potatoes. The food form is really best, but it is hard to be sure of the K content in each individual food. Also, go gradually to allow your organs to adjust to getting more. I recommend a gradual increase in about every situation outside of acute reactions.
I found my salt substitute at my local Publix, but they usually carry it at any conventional food chain. I didn't check my Whole Foods store, but I know that I couldn't get it at my other natural foods store.