2) no, it will not repartition the device but only restore the contents of the data and system partitions. but depending on the rescue package this may result in a shrunken data partition file system, i.e. data partition is still enlarged, but file system "thinks" it is smaller. can be fixed by formating the data partition, e.g. via hard reset.
3) Starting from the very first root package / firmware version, I never saw a rescue package rebooting by itself. They worked, but you always had to reboot manually.