I agree with colin, the algae looks like Caulerpa more i'd say, i would be carefull with it though as it can grow rapidly and take over the tank. I know this from first hand experience as i'v got some in my tank that i just can not get rid off and it even tries to grow into my corals!!
the green thing however i am not too sure about but at a guess i would say it is some sort of sea snail/slug...