I tested Heroic Quickness with a Harbringer (sent 15 at an indy on a test map and got lucky).
With no equipment or bless:
Basic Action Points: 16
Heroic Ability: +98%
Current Action Points: 31
With Jade Armor:
Basic Action Points: 16
Heroic Ability: +98%
Current Action Points: 46
With just W9 Bless:
Basic Action Points: 16
Heroic Ability: +98%
Current Action Points: 46
With W9 Bless and Jade Armor:
Basic Action Points: 16
Heroic Ability: +98%
Current Action Points: 46
So, stacking Heroic quickness with either spell quickness or W9 bless quickness works, but it is:
AP = (baseAP=16) * (1 + (heroic=.98) + (quickness=1))
Edit: wrong!
It's not base * 1.98 * 2.
Edit: wrong!
For some reason spell quickness and W9 quickness give the same boost when stacked with Heroic Quickness!
Edit: No no no! KO has corrected the error of my ways, I forgot to take encumbrance into account. My next post is more correct.