Dec 8 is that last day for actions. They have to be resolved by the 14th, which Is the day the EC meets and votes.
See my tagline.
Research the Election of 1876 and see what happened to the “deadlines” there.
Spoiler alert:
The final decision was not made until one day before President Grant’s term expired.
One day!
That is the only constitutional requirement.
All the rest can be changed by court decisions.
Thanks for the clarification, much obliged.