1.) During the numerous wars since the failed partition plan, has Israel virtually taken over Palestine?
Up untill 1967, Israel did not hold what is now reffered to as the 'Palestinian Territories'. During the Six Day War in 1967, Israel magnified its size by 3.5, reclaiming back much of its old territory, along with new one, namely the Gaza Strip and Sinai, two areas that were never a lasting part of Israel throughout its several-millenia existence, laying under its hold for a mere few decades at a time (and where therefore discarded as time went by). However, one must remember - there is not Palestine and Israel, but the two words are simply two names for the same piece of Earth.

2.) Does Palestine essentially exist anymore? Or are all modern day Palestinians living in Israel?
Palestine is Israel, in essence. However, today, due to demographic and historic changes, most of the Palestinian Arabs live in Yehuda and Shomron and the Gaza Strip (that has recently been discarded by Israel), where Yehuda and Shomron (Judea and Samarathon, in 'English') are historically Jewish and Israel, and Gaza isn't. However, now these areas are heavilly populated by Arabs, and they are reffered to as the 'Palestinian Territories'. That is, areas taken over by Palestinian Arabs, which now live there.