Actually, foreign policy is hard because most of the issues and problems it deals with cannot be solved, only managed. Kushner’s own political views, to the extent that they are known, seem to be liberal Democrat. His take on the Mideast conflict, for example, alarmed many conservative Israelis.
This is not a hard problem in any intellectual sense. It is a hard problem only because of entrenched interests who can't see beyond the short term. Trump's genius, even if accidental, is to incorporate varying views into his cabinet and advisors. Hopefully there are lots of supporters of Israel and a Jewish Israel, I would be surprised if there are not. Thus I am not concerned about the two state proponents like Kushner if he is one of those. Trump will be balanced and consider all the ramifications. He is not going to support a bad deal to make himself look good. That is not his modus operandi.