A faint line is still a negative. If youre home tests have been consistently negative with the first mornings void, then youre good to go. No need for any dilution techniques. Just drink enough fluids on the day of the U/A to where you can produce a sufficient amount of sample.

As far as your creatine questions go, any creatine-loading must be done at least 3 days before the scheduled U/A to allow the body the required time to convert the creatine into creatinine. Creatinine, being the end waste product, is whats found in the urine and tested by the labs to determine an overly-diluted sample.