Does the listed heavy armor bulk account for the padded armor and gauntlets, or do I need to add that on top separately?
Bulk tends to be an abstraction so I would say yes, the rules however don't seem to say one way or another except with this as guidance.
"This entry gives the armor’s Bulk, assuming you’re wearing the armor and distributing its weight across your body."
But people fall on either side of this as well regarding the "bulk of a creature rules" and whether that is intended to represent the abstraction of the whole creature + equipment or a part of a simulation and needing the GM to calculate all the bulk the creature would be wearing on top of it's base bulk.
Hopefully the upcoming errata will touch on this as it was hotly debated.
Has a date been suggested for when the errata will drop? Hopefully before GenCon Online?
Before the APG release is the only hint we got. But things change and they may go back on it yet :(
Does the listed heavy armor bulk account for the padded armor and gauntlets, or do I need to add that on top separately?
I am assuming that only becomes relevant when someone opts to sleep in padded armour?
This is my personal take on this: Since heavy armour includes padding and gauntlets, yes, the listed bulk accounts for that.
However, since bulk is in large parts an abstraction, if someone would announce to only wear padded armour and gauntlets, and stuff the rest of their plate mail into a backpack, I would still make the packed up suit of armour count for its full encumbrance. You know, to avoid shenanigans.
If you rule that plate mail minus padding and gauntlets only takes up 3.8 bulk of backpack real estate, that probably works too though.