The Clintons at least got to be pretty close to the Bush family, and I think the Obamas got along with them as well. Carter's a Democrat so if anyone avoids that funeral I'd think it would be the President.
There is no love lost between Trump and the Obamas or Trump and Hillary. Franklin Graham's a birther who claimed Obama was a Muslim. I'd love to be a fly on the wall on the slim chance those two ever meet again. So the story isn't that neither are coming. The story would be if either one did.
Good points.