1- Many meanings have been mentioned for Yahweh. One meaning is “the Creator,” and this is one of the names of God.
2- No it is the same God. However, the people of the book have prescribed false attributes to God, such as Him having a son. But they are referring to the same God that Islam calls onto. The same one that Prophet Ibrahim called on to.
3- Originally Yahweh was not a personal name. It was one of the names of God. Some Jews started to treat it like a personal name when they started to ascribe personal qualities to God.
4- Yes, we can, but we must make sure we are not doing so in a context that appears to be condoning Jewish beliefs.