Welcome back, Kori.
That error message tells me that you are trying to convert an integer value (which ads1115PinReader(i, j) undoubtedly is, into a pointer to a function - one that takes an integer as its only argument and returns an integer. And that doesn’t make sense.
I’ve no knowledge of the ADS library, nor the version of emonLib that you appear to be using; but surely, and assuming that ads1115PinReader( ) returns one instantaneous reading of the ADC, you should be using that method inside emonLib’s calcVI(...) in much the same way that analogRead( ) is used, and then picking up the value that emonLib has calculated, as in power = ct1.realpower?
I think you need to find some documentation about that version of emonLib and if there are examples, study and understand them.