Ike's B up is pretty predictable, but it's still hard to edgeguard because he'll be coming in low and has super armor. Gale guarding is fairly useful against Ike (jump off the edge, and throw the boomerang at the edge; it'll bounce off the edge and blow Ike backwards if you aim it right. It can take some practice). You can also try dair, but you'd have to time it just right to avoid Ike's super armor.
I suppose the classic way if Ike is aiming to grab the edge is to grab the edge right as Ike pulls up his sword to throw it up, then right before you would lose invinciblity you can roll back on stage (being at 100% makes you roll back up slower) and if you time it right Ike will fall down while you're still on the edge. If you're feeling particularly ballsy, one thing I liked to do to my roommate was to short hop off the edge backward right as Ike pulls up his sword, airdodge through the sword spinning, and tether the edge once you're past the sword so Ike falls straight down, since Link stretches his body outward when he grabs the edge. The second option probably isn't as great, but it does make you feel like a man when you pull it off
Edgeguarding is definitely something you'll want to work on as Link. He's best at stopping people getting back on stage from the ledge, and can rack up lots of damage this way.
I don't know a whole lot about other controllers; I've always used the Gamecube controller to play Brawl. So I can't really help you there, sorry. Hope this helps.