Thanks Zap 

1/Yes, "any" is the key. I was not sure if they could really reroll "any" dice 

2/Yes, it's this card. So it means that even is 2 warhounds (or 2 questors/subjugators) are in the same detachment and do not have to remain in coherency they have to be actived together and have the same orders.
3/"any weapon that uses a template and has xBP instead of attack dice" sounds better for me. Eventually, this may just be placed in the description of the "Glamour of Slaanesh" or holofield for eldar titans.
While we're in the questions, maybe it's historical but why all the standard SMC are Elite ? I do not really understand why they're elite but standard SM are not...