HI
I have dark brown hair and a genetic white streak (skunkish) in front.
I would like to experiment with coloring the streak.

1. Any recommendations for a true "temporary" hair color that will completely wash out after few washings?
2. Any recommendations as to a color for the streak (not gold/yellows, I am fair skinned with pinkish/red tones)?

There is no such thing as a color that washes out in a shampoo or two. Howvever, You can try a demi- permanenet color and it will fade over time. The only thing is, that with it being white, it will be resistant to color so you would probably be better off going to a salon and asking them to do it. I work at the smartstyle inside walmart and we only charge $5 per foil for something like that... it's worth it because you never know what you're getting with box color

Good idea. I used a semi before and am now awaiting the grow out period because it did not fade, at all. And you are right, the streak takes and pulls color differently than the rest of my hair ever did.
Thank you for your advice.

You are very welome