I doubt it. I figure Kerry only accepts tightly controlled Q&A sessions, and he wasn't confident that an appearance on O'Reilly would help him. There isn't much downside, if any, in not appearing.
Nope. John "Irish" Kerry hasn't held a news conference in a long time and only does interviews where he knows he will be treated like royalty. Kerry has/had nothing to gain by going on O'Reilly.