Good grief. Lorikeets :nilly:
Best of luck - you're going to need it and a hell of a lot of patience.
Do you have any specific goals you want to achieve?
Axy's should be kept with sand; massive stones they cannot swallow or nothing at all.
Remove what's in there with him. He's probably eaten one of those stones.
Because it will be in equilibrium with your KH. Adding more CO2 within reason won't lower the pH but talking it away will make the pH bounce back to normal levels over time.
Get a broad range tester that will give you a better indication as far as what's going on with the pH.
That range is quite normal and nothing to be worried about.