Anything that fits in your pikes mouth will be considered food. The gouramis will end up missing and depending on the size of the JD's when you get them, there will be some aggression. If its a bonded pair of JD's, then they might stand a chance against the pike, but the c. johanna gets 12-14 inches and the jacks get 10.
Not sure if you have dithers, but they will take the tension away from the cichlids.
You're gonna needs lots of places to hide, but no actual caves. Make your hiding places with two entrances, that way your pike wont feel extremely territorial.
And a much bigger tank. You may also find it tough to keep both species long term because of the different parts of the Americas. Pike is from SA and JD's are from CA.
Good luck
