Four eh? How big are they? Really hope they are two males and two females....doesn't seem like he had any big enough to sex accurately yet...unless you got some over 6"...then it migh be a bit easier. Great pike up...lol...LOVE them.
You can feed them practically anything. I got my 5 from Anthony yesterday (Tuesday) and by last night I had mine eatin - krill, mysis shrimp, brine shrimp, cocktail shrimp, and beefheart. So they can be taught to eat other things...
. Get them fat on guppies first since they are gonna be STARVED from the trip, then after they eat all of those start gettin them on mysis, bloodworms, blackworms, cocktail shrimp, and krill. The mysis, bloodworms, and blackworms will be the easy part. Other foods might be easy. All pikes can be taught to take prepared foods like pellets and sticks....my 'mystery' pikes already do...and the marms are interested in them already. 
You can feed them practically anything. I got my 5 from Anthony yesterday (Tuesday) and by last night I had mine eatin - krill, mysis shrimp, brine shrimp, cocktail shrimp, and beefheart. So they can be taught to eat other things...