Two snaphosts (YOG4 & XNG3)? & Cyan recovery versus TWRP?

Hello,

Hammerhead snapshot page (https://download.cyanogenmod.org/?de...&type=snapshot) has two snapshots (YOG4 & XNG3) released on the same date (Sep 1 2015). Is one CAF or does one include google wallet? Why two files?

Also, two cyanogen recoveries are being shown. Can TWRP be used instead?

I am going to try dirty flash over 26 August nightly. Is this after the cut off date? Does it matter?

Thanks!