Well, I aint sure if we should discuss him first, but in hopes of help:
-A few basics
He is one of those difficult ones, weight, power, good recovery, good speed and mobility (for a heavyweight), all against Pit. His air camping also is very frustrating, and degrades our camping quite a lot, and makes it very difficult for us to hit him.
Both Pit's and Wario's range are close, but we probably have a bit of longer range with some moves, though lower priority. That's where spacing F-airs may have a use, but try not to use too many arrows since Wario can close in fast, not just by Bike, either; but his own decent speed, and his DACUS too, which can go quite far at its max distance.
-The Bike and its Tires
The Bike isn't that big of a threat. You can counter with a basic shielding, a D-air, maybe a SH N-air (not sure yet), a Pivot grab, or just jump outta the way. Just try not to get hit by it if you somehow are around 150%+ damage, and then it could probably kill if you are close to the ledge.
When the bike is destoyed, you got the 2 tires. Wario doesn't have a glidetoss that makes him slide far, but ours can. We could use it if we are at quite a distance from him, and use the glidetoss to quickly close in towards him, or if we need space away from Wario, glidetoss away from him, and then shoot an arrow. You should know that Wario's bite allows him to eat the tires if we throw it torwards his mouth. Also, when Wario throws a tire upwards or downwards, and when it bounces, avoid it til it stops completely, for will hit you, and this can be frustrating when you are between a bouncing tier and a Wario. We can use that strategy to our advantage when we control them, too.
-Grab scheme (or whatever to call such)
Okay, we obviously can't CG Wario with his floaty self, nor we can do the F-throw to Stutterstep Fsmash on a DIing Wario, so that limits us. Now we do have a grab release on him, ONLY IF THE WARIO STRUGGLES OUT or if we somehow grab him to where he is hanging off a ledge (what are the chances?). Should this happen, we can do the following:
-B-air (good for a kill)
-F-air (a damage option and you can push him back a bit)
-D-air (a damage option, and you can send him to the air, somewhat lethal for killing when Wario is at 170%+ damage)
-Usmash (not completely effective, but could help if you want him in the air)
-Fsmash (This isn't certain yet due to the need of more pro testing. Should this work, we are to quickly do an Fsmash ASAP, and though the first hit wont connect, the 2nd hit should, and that's one of our KO moves. This can be a decent killing alternative if we have a stale B-air).
Again, Wario either has to be hanging somewhere, or struggle out a lot to be air-released (don't pummel the moment he breaks free or he is forced to ground release), so keep that in mind, and don't rely on it too much against a smart Wario.
-Gimping: Pit to Wario
Gimping him is almost impossible since he not only has a good recovery, but can maneuver around in the air to dodge some of our attacks. What he has for a recovery are the following:
-Mid-air jump (that's obvious)
-Bike (that and jumping off of it for higher elevation)
-Up-B (Again, obvious)
-Fully-charged Waft (This is more of an emergency use and a situational type of thing)
All that plus air mobility, and he pretty much is a hard one to knock off. So um, good luck gimping him. However, should we ever get him to his Up-B only, he is somewhat easy to edgehog if we can time it.
-Gimping: Wario to Pit
Now, Wario can gimp us a bit if we are not careful, but we got a lot of options, from our 3 mid-air jumps to gliding under the stage (IF the stage grants that), We can shoot arrows as we move, or F-airs, and with Wario's poor range, we shouldn't have too much problems, I hope. Avoid PS1, PS2, and YI (and Castle Siege) if you want to glide under the stage, and you will need it so you won't get gimped as much.
-On the Defense
Pit wil probably have to be defensive since Wario has a string of quick and multi-hit moves (D-air, N-air, F-air mostly noted in these categories) like Pit, and it can pressure your shield if you don't get outta the way fast, though we can shieldgrab sometimes depending on where Wario will go after his attacks finish.
As for when we are on the ledge, it is hard to deal with him. His bite should keep much of our stuff at bay, from us airdodging onto the stage, and I believe F-air (it has super armor frames when we hit him and he catches us at the same time), and his air camping should allow him to avoid much of our arrows. Hopefully we can deal with this somehow.
I feel that this would be 40:60 Wario's advantage, let alone that he can get past our arrows easily and catch up to us kinda well, sort of like Marth, except Wario has much less range, but is heavier and has a much better recovery that is very hard to gimp.
As for stages, not much is known to me yet, but do stay away from Japes and YI.