The falling stars represent fallen angels is a correct analogy, the mountains we are told what they represent, kings, in Rev. 17:9-10 and waters or sea represent people.
Yes you are right the bible does use stars as symbolic representations of Angels and in Revelation i believe the following scripture is symbolic of angels.
Revelation 12
3And another sign appeared in heaven: behold, a great, fiery red dragon having seven heads and ten horns, and seven diadems on his heads. 4His tail drew a
third of the stars of heaven and threw them to the earth. And the dragon stood before the woman who was ready to give birth, to devour her Child as soon as it was born. 5She bore a male Child who was to rule all nations with a rod of iron. And her Child was caught up to God and His throne. 6Then the woman fled into the wilderness, where she has a place prepared by God, that they should feed her there one thousand two hundred and sixty days. 7 And war broke out in heaven: Michael and his angels fought with the dragon; and the dragon and his angels fought, 8but they did not prevail, nor was a place found for them in heaven any longer. 9So the great dragon was cast out, that serpent of old, called the Devil and Satan, who deceives the whole world; he was cast to the earth, and his angels were cast out with him.
I would feel more confident in revelation 6 being a representation of satans angels being cast down to earth if it mentioned them as a third.
Revelation 6
13And the stars of heaven fell to the earth, as a fig tree drops its late figs when it is shaken by a mighty wind. 14Then the sky receded as a scroll when it is rolled up, and every mountain and island was moved out of its place.
See how it says "the stars of heaven fell to the earth" not 1/3rd of the stars of heaven fell to the earth?
i feel the book of Revelation is a blend of both symbolic and literal. I believe it was delivered that way for a purpose That is to hide its meaning until the times in which it is needed and to hide its meaning from those whom God does not want the message revealed.
As for the 7 mountains depicted in rev 17
Revelation 17
9"Here is the mind which has wisdom: The seven heads are seven mountains on which the woman sits.
I have no strong feeling on what they represent. I do not know. i have heard that they are the mountains that the city of rome stands on i have also heard they represent 7 great empires that have supported the babylonian religion, the whore. And now you have them as 7 kings? fair enough. Oh one thing just popped into my head while i was writing that. i am thinking of that stone that crashed into the statue with the iron and clay feet and that scripture goes on to say that the stone grew to become a great mountain that
Daniel 2
34You watched while a
stone was cut out without hands, which struck the image on its feet of iron and clay, and broke them in pieces. 35Then the iron, the clay, the bronze, the silver, and the gold were crushed together, and became like chaff from the summer threshing floors; the wind carried them away so that no trace of them was found. And the stone that struck the image became a
great mountain and filled the whole earth.
We know that the returned Messiah will be the leader of the kingdom of heaven on earth. So i see the mountain that filled the whole earth as symbolic of the Messianic kingdom. What do you think ?
Blessings to you FieryIce
All praise The Ancient of Days