Alkainty is carbonate hardness. It measures the buffering capacity of the water. In other words, the ability to keep the pH steady.
Edited to add:
You will be fine with those test kits unless you start dosing specific trace elements. If you add something, you test for it.
If you have a nuissance algae problem, you may want a silicate test kit if your PO4
test isn't positive. Other than that, you got the essentials IMO