Re: P0700 Code
The P0700 code only tells that the transmission control module has set a fault code. Now you need to scan the TCM to see what fault code it has set, the key dance will not show that. How does the transmission shift?
Loosing power and the rough idle seems to be more engine related. A TPS sensor for example, eventhough you would expect a fault code for that one. I would first do the TCM scan and depending on that decide what to change.
Did you do the keydance after it lost power, or before? Do it once more to see if anything changed.