As for the first question, I think those faces are 'corps candles'.
Gollum to says that in his own unique way: 'The tricksy lights. Candles of corpses, yes, yes. Don't you heed them. Don't look. Don't follow them.'
These things are undead, luring you into the pools with these lights (in this case the lighted faces)... how exactly I do not know. If you look at them they kind of absorb your energie in some curious way. That's all I heard of these weird undead.
As for the second question: I think Gollum too was under lured by them and tried to reach them. How he became free of them I do not know. I kinda wondered about this question myself some time ago.
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'You?' cried Frodo.
'Yes, I, Gandalf the Grey,' said the wizard solemnly. 'There are many powers in the world, for good or for evil. Some are greater than I am. Against some I have not yet been measured. But my time is coming.'
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