If I have it on the day of the interview, I have a little less than 48 hours. Will tomorrow be too late to get creatine?
That would depend on whether your creatinine level was low to begin with. Do you normally drink large amounts of fluids as part of your daily routine?

Will drinking plenty of water and taking vitam B be enough?
That would depend on your smoking history and length of abstinence prior to the scheduled U/A.

Dilution techniques are geared more towards lighter smokers and those who've abstained for some time. Dilution techniques can backfire if the THC metabolite concentrations are too high. For most heavy users, its impossible to dilute without overdiluting and sending up the red flags.