Yeah, psychometry was pretty much what I was thinking of. If Leo ducks into some maintenance cabinet or similar easily-concealed space, I think I can cover us for a long enough time, given that Kitty can herself use thaumaturgy-level illusions and veils on an evocation timescale.
As for complexity, it's really up to Boz, but for a quick and dirty estimate, we're looking for one or more scene aspect assessments here and want to go back a few hours in time. The time chart on page 315 is a fairly good guideline for thaumaturgical spells that work over X timescale, starting wherever the GM deems appropriate. So assuming we start somewhere between "instant" and "a few minutes", the shifts from time would be somewhere between 8 and 4. Add to that the difficulty of the scene assessment times however many aspects we want, and I'd estimate the thing as anywhere between 7 to 16 shifts.
As preparation goes, we do have three aspects from Leo's use of the Sight, all of which should be applicable to this ritual, since they're directly related to the nature of what happened. So building on Leo's Lore of 5, we could get off a ritual at up to 11 shifts fairly quickly. Given that they heal supernaturally inhumanly fast, Phil and/or Kitty could also donate a minor consequence towards it. How long the actual casting takes is fairly blurry and largely up to Boz.
Alternatively, we could go to one of the PCs' places, which would likely be closer than Ziggy's, to do the ritual.