You can find the standard/stock basic FET+1 schematic here in DEL's driver thread: https://budgetlightforum.com/t/-/44006/3
It shows the 7135 on pin #5, FET on pin#6. Pin #2 is the switch, pin #3 is the switch/AUX LED, and pin #7 is the voltage divider (not really needed w/Anduril).
Yes - Q8 is same as D4 but with the add switch LED on pin #3.
Not sure about the latest .HEX files.
DEL has the parts list (BOM) in his OSHPark listings, like here: https://oshpark.com/shared_projects/qsbLVgh0 or here: https://oshpark.com/shared_projects/pYGsJoAx
DEL developed the first stable, proper designed driver for the ATTiny85. He designed the Q8 driver. Everyone thereafter copied his design, or I passed along the info to them.