broken intake water outlet tube

That's a better solution than putting an NPI intake on

Really, that should work just fine - the base of the water outlet looks plenty thick enough to support it. The only thing I'd worry about is how well the threads will hold up in the plastic - I'd probably want to epoxy it in there to make sure it didn't blow out at some later point but if has as many threads as the top of that tube does then it may be fine without it. At the very least you need some thread sealant though - maybe that's what that white stuff is in the first pic.

Looks like a fairly permanent repair to me. Good job