Grief fire makes smoke--capable of rearranging molecules in a complicated way.
Yet another example of such rearrangement, and its mundane suppression. Neither the candy-wrapper smoke nor the fire imparts magic or Grief to the air it interacts with.
Grief-based smoke suggests that it would be obvious in the above experiments if the air were being imbued with Grief in order to affect its motion.
The light does not become magical or Witchy--it's just the sphere that avoids deflecting it.
Magical and Grief-based effects are undone when they leave your range. Mundane effects are mundane, with no magical or Grief-based substance to be undone when they leave your range. The experiment with the phaser was silly, I'll add, because an actual laser, rather than a magical sci-fi device, would almost certainly have worked.
Taken together, I believe the requirement of Property 3: to avoid disturbing the atmosphere in spite of a high speed vehicle moving through it, has good evidence in favor of its feasibility. That is what I called "conceptually tested" about it.
Gravity experiment described gravity as "easy". Careful not to make a black hole. The gravity is produced by Grief, and Grief responds to your will in complicated ways, so Property 2 also has good evidence in favor of its feasibility.
Because a teleporter would quite possibly run afoul of the range limit, and the rhetorical environment is unfavorable to Grief projects that have a significant chance of being unfeasible in an uninformative way. Thus, I make a specific proposal for a device that is barely less functional than a teleporter, if at all, that is virtually certain to work as described.
Actually, the teleporter would probably have to be stored rather than created on demand in order to be faster overall. The vehicle I described would probably be very easy to produce--I noticed that Sabrina seems to do mundane effects with Grief almost instantly, and it's the magical/nonphysical stuff that takes more time. For distances the size of Mitakihara, the difference between 10+ km/s and infinitely fast is mostly irrelevant.