It's not extended who died only, the real bummer is that the vast majority of those libraries were dead before the plug was pulled from extended, and for all that is worth, you can still download them into vanilla. Not much would have changed if it was around.

Just look for externals that are actively being developed and easily available

I'm creating a wavetable using sinesum to write harmonics to an array, which works fine for integer overtones. I'd also like to be able to be able to write non-integer overtones and undertones to the array.

If you put a 2.5 cosine harmonic into an array (2.5 cycles spanning the array's length), then the beginning of this wave will be +1 and, at the end of the array, -1. So you'd get two full cycles, then half a cycle going down, and then jump abruptly to the start again. So, non-integer partials will always behave like hard sync.

If you want that hard sync sound, that's fine, but if you want a smooth wave at 2.5x the fundamental frequency, it's not possible with a wavetable (unless you size the wavetable according to the LCM of the partial ratios and scale all the ratios up to be integers).

hjh