My pinkies wake up a good 15 seconds after me.

Factual Questions
1

Yes, you heard me correctly. My little fingers.
When I wake up there is no feeling in my littlest fingers.

This worries me… that unthinking I might snap one of them off by snagging them on blanket or something (as there is an utter lack of feeling in them I don’t think I’d feel any pain or even know I’d done it)
It used to be whole arm(s), but that doesn’t happen anymore.

2

Get checked for diabetes, assuming you have eliminated sleeping position as a cause.

3

Is it both pinkies?

This happens to me all the time, but only on one side, and if I sleep on my back, it doesn’t happen.

4

See a doctor if it happens regularly.
Currently it may be a mere nuisance or less, but it could indicate a problem with your blood circulation.