Yes, instructions are a bit confusing as most of it is unnecessary on Jessie (full or lite). there should soon be a one-line-installer available that should make things simpler and support both old and new.
Re pins used by the pHAT DAC, @gadgetoid has to confirm but I suspect it would be BCM 18,19,20,21 for i2s, combining it with other add-ons shouldn't be too difficult.
