Well, you're making multiple inaccurate statements so I'll break it down for you:

1. Hamas has major influence in the west bank. They hold over 50% of the seats in the Palestinian legislative council.
2. Hamas and the PA have identical objectives: to eradicate the Jews as a nation in the land of Israel and (best case, after not having killed them) turn them into a dhimmi - a subjected minority subservient to Arab/Islamic rule. The only difference between the Hamas and the PA is methodology and branding: hamas are islamists whereas the PA is neo-marxist. As we say in Israel: "These are murderers with beards and these are murderers with mustaches." I suggest you read the charters of the PLO and Hamas. Not only that but PA "policemen" and members of its military wing's Al Aqsa brigades were and are regularly involved in terrorism and premeditated lethal attacks against civilian men, women, children for no other purpose than to see Jewish blood spilled.
3. There is no such thing as a Palestinian national entity. There never was and there can never be. "Palestine" was the name given to the province of Judea by Hadrian after he decimated the Jewish population of the province in the aftermath of the Ben Kuziba (kochba) revolt in 135 CE. The following occupiers of the land (Byzantines, Arabs, mamluks, Ottomans, British) retained the name as a geographical designation and nothing more. In fact Jews themselves prior to the founding of the state of Israel referred to themsleves as Palestinians, not as a national identity of course, but rather as a geographical identifier.
4. The Arabs present in the land first came as invaders and occupiers in the aftermath of the Islamic conquests and expansion in the 7th century - and then just as a trickle. Until the 20th century it was sparsely populated by mostly poor illiterate Arabs and considered a backwater of any empire ruling over it. No conqueror gave it much though as it was a barren desolate land. In the 1830s as a result of Muhammad Ali's rebellion against the Turks, in which he established semiautonomous rule and handed out lands to his supporters did the land see an increase in its Arab population, but even then very moderately. In the 20th century as a result of the establishment of large scale agriculture by Jews which demanded labor, more Arabs from surrounding countries came to settle in the land, as the estate holders preferred cheap Arab labor to more expensive and less experienced Jewish labor. The Jewish presence in Palestine goes back to over 3500 years when Abraham first moved to the land after receiving a directive from the most high and his son Isaac and grandson Jacob establishing autonomous political Hebrew entities. The land from then on was consecutively populated by Jews/tribes of Israel as sovereign majority rulers and Hebrew kingdoms and national federations were established and maintained for the course of over a millenia (barring the subjugation in Egypt and Babylonian exile) at its peak extending from the Nile (el arish) and red sea to the Euphrates. The land was known in the world as Judea and Israel [and its people Jews and Israelites] (until 135 CE as mentioned above). Therefore, any notion of Jews stealing land from foreign occupiers such as the Arabs who call themselves Palestinian is a fiction of the basest form. Notwithstanding that, 80% of the land in the west bank is public lands (a status inherited from pre-1967 Jordanian occupation) and by common and international law falls under the jurisdiction and custodianship of the ruling sovereign who in this case is Israel (the Israeli shekel is the currency in circulation in the west bank and Gaza). The property rights of the remaining lands that are in private Arab hands are actually respected and enforced by Israeli courts and administration. There are many court decisions in favor of Arab landholders in the west bank. Feel free to search the internet to verify that I'm not BSing you.
5. Israeli rule initially respected the natural rights of all Arabs in the west bank and Gaza but as the years progressed and the Arabs demonstrated that their priority was to kill Jews rather than live peacefully the IDF had to resort to violating their rights as common law would dictate.
6. The settlements weren't established with the stated intention of creating a buffer zone (even though this is de facto what they function as, and justifiably so) but rather as a materialization of the right of Jews to fulfill the divine statute of settling the land and preventing foreign occupiers from stealing the land. Regardless they function, now more than ever, as a major buffer and are strategically located in such a way that makes it much more difficult for the Arabs in the west bank cities to organize and launch full scale terrorist attacks against major Jewish population centers.