capsicum = pepper (in all colors: green, red, yellow, orange)
“get it sorted” = figure it all out, get things organized. In the states people certainly talk about “sorting something out,” but that nearly always implies that there’s something wrong (a missing dinner reservation notice, for instance). Here in NZ, it’s a less judgmental and more neutral phrase that doesn’t mean anything is wrong but that a certain matter requires attention.
“my shout” = I’ll treat, I’m buying (food/drink)
cruisy = easy-going, flexible
biscuit = cookie