a mix of info from my extra source, and from tv guide ...also the extra that I get the info from, when anna lucia was calling her mother last night from the airport saying she was coming home, he was walking in the aisle behind her heading towards the camera. He was wearing a blue shirt. On the island, he always has a red shirt on.
the season finale will have a large object in the water, no specifics on what it is, (maybe has something to do with the space ship stuff)
locke and mr ecko will come to blows
libby will have a funureal...but there has been speculation on tvguides website that due to the islands healing ability, characters may have the possiblity of coming back...look at abrams other work, alias, to see how characters never really die.
walt will be back
my own speculation about mike and the people he wants to attack. Maybe those other people aren't the ones in charge or even took his son. Maybe they are just like them, stuck on an island, sort of being told what to do by some stronger group. As he said he saw no boat, only saw 2 guns, and mostly women, children and older people. Or maybe he is with them now.