That's it, it includes it all, even pending post payouts, anything in savings and any conversions you have going on from SBD etc. The lot (that's what I've been lead to believe from when I asked in the Hive Discord a day or two ago). So you don't need to powerdown for the snapshot.

However, I think a lot will be powering down after the snapshot and then using their steem to buy Hive to get a stronger position over there...