The two grammatically correct sentences are:
- "Editing is where art meets discipline," the keynote speaker said.
- "They told me I'd get a thousandthousand-dollar advance if I signed today," Martha said into the phone.
The first sentence is correct because it properly punctuates the quote and the attribution. The second sentence also correctly punctuates the quote and uses “said” appropriately.
The other sentences have grammatical issues or punctuation errors.