Now as for angels...
I said no. Angels are a Judeo-Christian-Muslim mythological creature- by mythological I do not mean false, but rather supernatural and requiring faith. Both Christianity and Islam rose from the foundations of Judaism, and Judaic scripture does not maintain that angels have free will, but rather that they are the messengers of God. Christians interpret Isaiah 14:12 as the fall of Lucifer, the Angel of Light, becoming Satan. However, Jews strongly maintain that this passage refers directly to Babylon and King Nebuchadnessar, as 14:4 directly names Babylon as the subject of prophecy: "you will take up this taunt against the king of Babylon." I am not sure why Christians interpret this as the fall of Lucifer and other angels, when it clearly prefaces the prophecy with the statement that it is about Babylon, which also makes perfect sense if you know the story of Babylon.
Satan, meaning "adversary," was the angel of death and temptation. He could only act in accordance with God's will, just as all angels did. Angels in the OT were not all about helping people out- they were also messengers of stuff people didn't want to hear. Satan tested people's moral fabric.
As a mystic, I do not think that the supernatural is limited to God and angels, so I have no problem believing angels are as the scriptures say they are- messengers of God, or extensions of His will, without free will, and yet still thinking there are other "supernatural" entities that do have free will. As one Irish woman put it in an interview- "You have God and Satan and angels over here, and faeries over there." That is, God and Angels (of which Satan apparently is one) do not preclude the existence of other realities and folks in them that we perceive as supernatural and/or spiritual, be they dragons, faeries, nature spirits, or whatever. I think, depending on our worldview, we interpret a wide variety of mythological creatures as fitting into systems to which they may not be a part. Thus, the faeries of the Celts became translated as angels and demons by Christianity, though people who believe in faeries and say they have experienced them say they are neither angels nor demons. I think some spiritual entities do have free will, but angels are not one of them, by their definition by the scripture of the cultures/religions that record them.