Okay. I'm going to give you two answers. Real life vs Game. I'm a defense maniac, getting my bachelors in coaching right now >.> Anywayyy long story short.
1. Trips on one side - It generally means a screen or a heavy run on that side. In real life you would have a Cover 2 play with a either a linebacker or a corner covering the flat because that'll definitely have a player. Then have a corner covering the deep and possibly a linebacker who can play zone over the middle. Generally if you're running a 4-3 or 4-2-5 then you want to go to a nickle package at least for this. In the game the best thing to do is decide if they're in shotgun or not. If they are, it's almost certainly a pass. I prefer a cover 3 in Dime. If there is a running back in the shotgun formation set the D-Line where it will run with a running back on an off-tackle play. Then shift the LBs over towards the trips.
2. Unfortunately zone always has wholes. Hence zone. The unfortunate part of this game is that zone rarely works, although I use it all the time. The computer will almost certain find a way to screw the zone up. Corner routes are a pain with zone, the best way to stop it would be a buzz zone as you said, the problem is, you're generally leaving a huge gap across the middle, but you also have to watch the deep zone. Offensive tip, if you can have a TE run a corner route and have a wide receiver go deep on the same side, you with almost always beat them with the TE. Man coverage pressed with a deep safety who can watch the deep field is the best way to defend against it. If you need any more help just message me. #1 D in all categories for 3 straight seasons