maybe we note in "Building Pd & the various WIP branches" wiki something like "mac/tcltk-wish.sh --arch i386 8.6.5" is not working?
I forgot about that wiki page and essentially rewrote it in mac/README.txt which now supersede it. Can you check that all the information is covered?
That is still up for discussion. It was only an update for Mac and not for any of the other platforms. Further, there are sizing issues IMO. I definitely want to update the icon but it should be for all platforms and agreed upon by more than a couple people on macOS. You can see a relevant thread on pd-dev.