This would be the most explosive implication.👇
"an assistant to the Vice President’s Chief of Staff called and informed me that President Trump had decided that the Vice President would not attend the inauguration in Ukraine. She did not provide any further explanation."
President Trump's decision to pull Pence visit was BEFORE a date had actually been set for the inauguration.
Upshot: Appears decision was to send a message to Ukraine. Not about a 'scheduling conflict.'