Please help me understand which rule of commas applies in these examples:

1. I frowned, but William just turned his head, trying to lead my attention to the lady with the question.

2. She was still leaning forward, tapping her fingers on the table, and waiting for my reply.

In sentence 1, do I have an indroductory element, plus a ?? -- don't know what the second one is.

In sentence 2 are my commas correct, and what do you call them?

a. Bracketing comma (parathentical element, or appositive)
b. Listing Comma
c. Joing comma (between a conjunction)
d. Gapping Comma (when you leave words out)
e. Comma to set off an introductory element