lost electrical power in Buick Lucerne 2007

Have you checked all fuses? Sounds like you could have a blown fuse of some kind. Especially when considering the lack of shifting from park and the key not coming out also as a result. Have a look at all fuses to verify first.

I have checked continuity for all fuses under the hood and under the rear seat. Are there any inline fuses to the starter or any where else? - Charles