True, though this is a spoiler-free zone unless I'm missing something and mistaken. In the fight with the Ick in the Erlking's lair
however Harry has already accepted the mantle of Winter Knight,
and I think this can be ruled as one of those situations where his sponsored magic talent will permit him to perform Thaumaturgy with Evocation's speed, so you can't really use that to justify Warden Bob in Miami having rapid worldwalking.
What about Agatha? And facing down lea by eating the death shrooms? :)
Theoretically, if the veil between the real world and the Nevernever is especially thin, you wouldn't really need that much in the way of complexity to open a portal. In fact, purely mental constructs would be all that is required. And considering the repeated weakening of said veil that allowed Kravos and Harry to create powerful ghosts, and then the Darkhallow,
The veil between has been very tenuous at best in Chicago. Harry wouldn't need to do much.
Even just mechanically, how long does the ritual have to be? If you have "Great" Lore or better, chances are you won't need to spend much time at all as you can hit it easily. (the no-prep "clause")
Well it wasn't like he grabbed the hem of her dress and hitched a ride. I can see aspects you've already noted as being on the scene and tagged. Weak Barrier [+2], Recent Transition [+2], At The Center of Her Power [+2] for starters, he's hit her with the dust so that's enough for a sympathetic link, and don't forget that Michael was right there too, and I'm pretty sure that would have helped tremendously.
In short this is a one-time special occasion that would use GM handwaviology to progress the story with the understanding that it isn't normally this easy to transition.
Compare to the battle , it takes Harry significant effort to open the door there and to keep it open. Ramirez has to keep everyone off Harry's back for at least a few exchanges while that happens.
This thread http://www.jimbutcheronline.com/bb/index.php/topic,21851.0.html (http://www.jimbutcheronline.com/bb/index.php/topic,21851.0.html) has some discussion about the length of time required for even a no prep clause ritual.