1. The KKK was founded by Christians who invoked their faith to support their bigotry. They use the story of Ham to support white supremacy and racial segregation. There are "Christian" churches that propagate racial and other kinds of bigotry (eg. the Westboro Baptist Church), but the fact that they root their bigotry in a perversion of Christianity does not make them Christians, nor does the perversion of Islam make terrorism "Islamic." Trump insisted on a lie: "radical Islamic terrorism".  Obama was right to avoid the lie and to speak the truth about terrorism.
2. Nonsense. It was Trump who pranced around the country lying about Obama's birth place. Obama was a young man of color, and Trump couldn't and can't stand it.
3. I addressed what you said precisely.
4. Obama spoke about terrorism precisely and correctly; Trump doesn't.
On Saturday, Trump did not name white supremacy as evil. Today he did, but it doesn't matter. No one, not even the bigots, believes anything he says.