The execution was carried out by the Fateh group of Palestine. The man being executed is a Hamas militant. Fateh wears very similar clothes/uniforms to the Israeli's, and lots of Palestinians look like Israeli's. The reason I'm sure it was not an Israeli performing the execution is because Israel never allows filming/cameras when they are around. Also, the propaganda writing is in Arabic and Israeli's speak and write Hebrew.
Yes, and Israeli's are mostly of the jewish religion, and do not shout phrases like "Allah Hu-Akbar".