ChabadShlucha,
Again, good luck getting any of the countries you list to take in millions of Palestinian Arabs. They won’t do it and frankly they shouldn’t have to. The Palestinians quite literally have nowhere else to go. You also can’t wish away the fact that they did live there before the state of Israel controlled the area. That’s the reason they are there now, they weren’t planted there as some sort of conspiracy.
The facts are that there are about 4 million Palestinians that are not allowed to have Israeli citizenship due to the demographic problem and aren’t allowed to have a state of their own. This is a problem. Giving them Citizenship would instantly make the country no longer majority Jewish. It would end Israel as a Jewish state. The numbers are what they are, whether you like them or not. So again, if you want Israel to be a Jewish state you can either give the Palestinians a state or kill them all, needless to say killing them all presents a serious moral problem.
The 3rd option is making a single democratic state in the entire area, in which the citizens of the country both Jewish and Arab can vote and have a say in the laws that govern the land this however would by definition no longer be a Jewish state. I don’t know for a fact but I am pretty sure that some of the Gedolim who opposed the state truly did foresee the practical moral issues involved with taking over land.