You are right about the drain for the fuel tank overflow, if you were to have filled that up too much it
should come out a hose at the very bottom of the bike where it wouldn't be dripping on the bike itself.
How much and how often are you adding oil? Any performance issues?
As can be seen in the photo you posted, the air filter has two things hanging down from it. One is a sight glass, that's a quick way to see if there is dirt, water, or anything else in the air box. Is yours full of gasoline? To the left of it is a pinched drain hose meant to let liquids out of the air box, without letting dirt in. There are some things the can cause gasoline to end up in the air box of a fuel injected bike, such as a malfunctioning fuel injector or a valve issue, but those are likely to also have noticeable performance issues (and uncommon sounds). Again, really the only place to start would be to track down where the fluid is coming from, then worry about how it got there.
From the owner's manual:
Checking the Engine Oil
- If the engine is cold, idle the engine for 3 to 5 minutes.
- Turn the ignition switch to the OFF position and wait for 2 to 3 minutes.
- Place your vehicle on its center stand on a firm, level surface.
- Remove the dipstick and wipe it clean.
- Insert the dipstick until it seats, but don't screw it in.
- Check that the oil level on all faces of the dipstick is between the upper level and the lower level marks.
- Securely install the dipstick.