yu dont yu get manure and use it tu get accross
You can't! They follow you on the ship, but they don't exactly help you at all.
You can't get rid of them, and there is nothing to do once you have the cheese and pull the lever. The way to reach the cell is through an underground passage from Mordred's Lab. (see the related question)
Three. If you just lure them away, there will still be three when you return to the Ice planet. You have to get rid of them. (see related question)
There is no reason to get rid of the librarian and his guards. You have already done all you can do in the dungeon. You opened the back gate of the cell, which connects to Mordred's secret underground lab. Go there and you can enter the cell from the rear. (see related question)
There are no fish. The Space Sharks are swimming around the Ice Planet, and the way to get rid of them is to let them chase you. Lead them up and right to the Black Hole at X-85 Y-47. (Don't get sucked in). (for more details see the related question)
You have to get near a space shark and lure it over to the black hole located to the north of the ice planet. Do not go into the black hole yourself, but circle it until the shark has gone inside. Do this for all three sharks and the way to the planet will be cleared.
The Astro was discontinued in 2005, so I'm not sure what a 2009 Astro would be.
At the Ice Planet, shoot one of the sharks and he will start to follow you. Avoid him and shoot each of the others until they are all following you. Stay just ahead of them and lead them slowly up and to the right to the Black Hole (X-85 Y-47). Fly along the outside of the hole and they will be trapped by it (just make sure that you don't get sucked in!).
Once you enter the dungeon with the secret McM stairway (with the Library Slip from the Museum), pull the switch, and get the cheese, you cannot get in that way anymore. The guards will not let you in. You can return to the dungeon through the tunnel from Mordred's underground lab. The guards will NOT block the entrance until you have the cheese and throw the switch. (see related question)
you have to find mordreds secret room(in between the hay barrels) and push on the dirt wall it will break. go into the tunnel and click on the open hole and you will be in the room that you were in before(thet the guards are guarding.
if you want to get rid of an island i think you have to start all over again.
take them into the black hole