1) Is PPV Kate the current preferred choice? Why does PPV work so well with Kate in particular? It seems that criminal plays the most events...is it because Kate installs it at a reduced price?
In my opinion (and most peoples'), Prepaid Kate is the best runner at the moment. Prepaid works really well with Kate for a few reasons, chiefly amongst them is the discount: it's worth noting that if you install Prepaid turn 1 click 1, you can then Sure Gamble up to 9 the next click. Another (of the many) reasons is that Kate already wanted to be drawing a lot anyway to make the most out of her discount, and it works really well with Event driven economy. Getting discounts on cards like The Maker's Eye, Legwork, etc, is even better.
2) If PPV comes out late, does the deck suffer? How does it generally generate sustainable economy? Can Magnum Opus be used?
Opus is a completely different deck that wants a vastly different card pool.
Without Prepaid, the Quality Time lists can struggle a little, but you still get a lot of econ from events.
3) What are the main uses of Scavenge? To recover Lady and re-position Cypher? To alter Atman's strength?
Usually to recover Lady, sometimes to re-position CyCy. It can do basically everything you can think of, though. I've used it to get things out of my heap, though, and I distinctly remember one game of testing where I Scavenged into an Atman from hand to break into a Susanoo-no-mikoto'd remote.
4) Which cards tends to be played most with Same Old Thing? Economy or tricks, or it depends?
Depends! If you suspect agendas are in HQ, Legwork's good, for example. It's very largely situation based, though.
5) Regarding the ice, I imagine Lady is taken as it is more efficient than Corroder? And Sharpshooter to break things Mimic can't? Is the decision between Gordian and Zu based on MU? How about Faerie and Femme?
Lady is significantly more efficient than Corroder (Eli 1.0 break costs alone is good enough of an argument).
Mimic and Sharpshooter combined with Atman get reach of all of the sentries you want, without paying a stupid price like Garotte, only to be paying 1 more than you should be for Architect...
Faeries and Femme cost influence. I'm a fan of a Sucker over Femme, as Sucker increases Atman's reach, but some people are different. You do not need Faerie at all in this deck!
CyCy + Zu is a decision that not everyone uses these days. I use Gordian over the place of both, but both Gordian and a CyCy + Zu mix is valid. I'd say not to have a CyCy + Gordian mix, though, you're paying too much for too little of a benefit.
And why is Deus X sometimes included?
I think it's for the PE matchup, but I don't know. I don't think that card deserves the deckslot personally. It's a dead draw in almost all games, and you can beat PE pretty easily without it.
6) When is Stimhack likely to be used?
To break a scoring window or just as a 9c econ card. It's a really good shout to kill what you suspect is a SanSan and get a discounted breaker out at the same time.
7) I guess I don't really understand the strategy of the deck at the moment...how is it played
Draw a lot, and don't run much. Prepaid Kate doesn't want to run through a Tollbooth for a single access. Other than runs to kill MHC/PAD or to run a scoring remote, she doesn't run much outside of through events.