Hello Paul,
I've not done any of what you've described in practice. I do own a Celestron Astrofi mount. This is essentially an old SLT mount with the wifi dongle stuck inside it. I say this, as I have an SLT also, and they look the same.
My impression (not claim to fact), is that the hibernation simply parks the scope in a neutral direction, and ceases the motor tracking. Meanwhile all the clock and location data is maintained. This means upon wakeup, a goto can be performed instantly.
Once the mount is powered down, the link to SkySafari would be lost, and all clock/location data is also gone. I'm not sure how you'd go trying to reconnect the mount and maintain this alignment, even if the SkySafari instance remained alive the whole time.
This instance of Hibernation is good to save the motors running all day, and more importantly, the scope hitting something as it tracks under the horizon as the day moves on. In any case, the mount, and the "brains" (iPad or laptop) need to be connected and left on. If done, with a very good initial alignment, you could indeed resume after some hours, days, etc.
It would be good to get some others' opinion on this. Especially in the realm of how Skysafari works if pushed into the background on the iPad, or iPad put to sleep, etc. The "Brains" does need to pick up where it left off for Hibernation to work. Hope this helps
