[X] The Pact of Passage sounds like the safest option. Some mundane people around town might get a little spooked, and the extra expense will sting, but it shouldn't involve any risks that are too terrible. Maybe some confused shopkeepers, at worst.
[x] The Pact of Warding has a lot of downsides, but it could reap serious rewards long term in the form of more native magic users. They'll organize sign-ups for a voluntary city-sponsored trip to 'Eastern Europe' in August. A lot of parents with elementary aged kids will want them out of their hair for a while by then anyway.
[x] All these Pacts are still too much trouble, better just to steal the bones and pay off the Rat King that way for another decade or so. The risks of getting caught red-handed by Wolfram and Hart are pretty massive, however.