Of the three youve listed, only creatine loading can help prevent a "too-dilute" ruling, due to low creatinine levels as a result of large water consumption

B2 helps restore color to the urine. But it must be understood that urine samples can undergo a validity check automaticly without a preliminary visual check. And urine samples with color to them can still fall below the acceptable limits for creatinine and specific gravity.

Using aspirin is old tech. Back in the day, it was used to interfere with only one kind of test - the first generation EMIT. As a result, a second-gen EMIT was since manufactured to tackle the aspirin issue. The first-gen EMIT is seldom used by the labs anymore (if at all).