yup
No you have to leave it for at least 3 weeks before you dye your hair. You can only use a temporary colour (that lasts one wash) until then but these they not over any gray coverage.
Yes, but you can get a funky color if you do it wrong.
Do you mean pastel hair dye? It depends on if you use a permanent dye or a semi-permanent. Semi-permanent hair dyes will wash out and fade over time; permanent hair dyes will stay in the hair until you cut it or dye it another color.
yes
Pick a hair dye that is specifically made to be used on gray hair, and the covering of gray hair. It will take to hair with no color for longer.
Yes, demi permanent hair color can be applied over any type of color. It will refresh the original color very nicely.
yes you can will it kill your hair yes but you can
Yes. Over time it will permanently lighten your hair.
yes but if you want to go red for instance you need to build it up
The only remedy for grey hair is to dye it black, and then be happy over the fact.
apply all over
Splat hair color is not a permanent color it is a semi permanent color over bleached out hair, once the melanin (color) is removed from the hair the hair is very porous meaning it absorbs like a sponge and the cuticle of the hair is open so once you have put a semi permanent over it which just deposits that cuticle is still open leading to the color fading out!