I resurrect this topic with an idea: a Reverse Reincarnation.
Not a character form a series who discover to be the reincarnation of a Nanoha character, but the inverse: a Nanoha character discover who seh was, in a past life, [random name] of [random universe].
Example?
Nanoha was Lina Inverse, Fate Amelia Will Tesla Saillone.