#1 I'm not sure what's circled there but I would guess sponge or something. If it's not motile I wouldn't worry about it for now. Also there is a large vermited snail jutting out to the left. I would break off all I can and glue the hole shut.
#2 That does look like a flatworm. I have cleared euphyllia of flatworms by performing repeated dips every 3-4 days until gone. You may get all of them in just two dips. The subsequent dips are for any that were eggs during previous dips as the dips do nothing to the eggs.
#3 I can't really make out what's circled but I see the euphyllia heads look like they're having some tissue recession. The flesh should be coming up over the lip of the skeleton and go downward. You're going to want to keep an eye on that and see that it's improving.
/And when I say dip I don't mean FW. I mean Revive/Coral RX/Bayer etc.