Your missing the point entirely.....Trump wants to do business regardless of country leaders ideology or where they stand on their home issues. Asean Sumit is all about that.
It was a last minute add on.
The President is not there to "break the ice" or any other such nonsense. He's there to suffer through Duterte and strengthen relationships with other leaders attending the summit. Hence, his trilateral meeting with Turnbull and Abe, followed by the unilateral dinner with Turnbull to focus on NK.
BTW, it's okay that the President is not thrilled to be there. It's not an insult.