"Plopping" question

For those of you who might not know what plopping is, it's esentially a way to wrap your wet hair in a Tshirt to enhance your natural waves/curls.

I tried this the other night, slept in it for a bit then in the middle of the night got annoyed and took it off, but still had some nice curls in the morning. However, I have two questions -

1. My roots were all flat due to the wrap, any suggestions which preferably do not include back combing to tackle this? I have just begun co washing again so no cones!

2. I currently have brown hair. Today I am getting it dyed pink again - will leaving my pink hair wet for so long leach the colour? I have always blowdried on cool with coloured hair to avoid rub-off on clothes.

Thanks in advance!