Hi Hans,
I’m sorry I’m late to the party and that I can’t answer your questions, but I wanted to call your attention to [shifter~], this is a PSOLA pitch shifter object that I ported to Pd from its eponymous version in Max-MSP, developed by Tristan Jehan. The source code and MacOS compiled library are here:
https://bitbucket.org/julovi/shifter/src/master/
Cheers,
Julian.