Your reasoning seems pretty good, but here is feedback. 1) The fact that 11 people were identified suggests a very strictly financial operation. Every country has people who could do a job like that in low numbers with much less exposure. 2) Hamas or Fatah would not have the capability to do that job the way it was done, even if it were to their advantage. 3) Egyptians would not seem to have a motive, certainly none that would justify the expense. 4) Because it was "high profile" and "low urgency", it is a safe bet that both the timing was taken into account and publicity was considered essential. 5) The timing suggests right wing Israeli commercial involvement. 6) The details make it appear as though the hitmen were hung out to dry by their employer. Letting them get blown easily, and then creating a complex trail back to Israel, will further distance the Israeli gov from the Pals, delaying peace and benefiting... take a guess...
4 UN peacekeepers injured in Sinai and taken to hospital in south Israel (Haaretz)
from the article: At least five Israelis 'share names with Dubai hit squad suspects'