Active hamas could be 50k-100k, men. Israel is going to kill/capture a lot of these.
Rest of world needs to ban hamas, and send their leaders to The Hague.
I think Egypt should build a temporary city, in Sinai. Identify everyone, dna etc. total search of everything for weapons etc. they sign an agreement to behave. They get 2 years of training, healthcare etc. you dont behave, 5 years in prison.
Rebuild Gaza, with seismic sensors, buy a citizen monitoring system from China. Recruit Gurkhas from Nepal/India and U.K., to make a police service. Buffer zones manned by un etc.
Build some factories, but with limited military use, I.e. plastic sun loungers, solar panels etc.