1. It isn’t a “hiddush” about waking up being compared to reviving from the “near death” of sleep. The idea appears in many cultures.
2. The way to date a tefilah isn’t necessarily by looking for the oldest “siddur” that has it, but to see whose siddurim don’t have and seeing when they split. If both Ashkenazi and Sefardi sidduring have something, it probably dates back at least to the period that the Talmuds were being written (before the Ashkenazi/Sefardi split). Physical sidduring don’t last very long since they are heavily used and wear out, whereas a nusach will survive and leave its trace on future siddurim.