Don't try the visine. It wouldn't pass the adulteration test. Creatine powder is pretty cheap at walmart.
I wouldn't worry about the aspirin either.
If you just drink 40 ounces of gatorade the morning of the test.
Piss 3 or 4 times and then use your midstream urine you should be fine.

B2 will not give a false positive. Even if it did, when they did the confirmation test it would show negative. There's quite a lot of outdates info on errowid so read with caution.