Yes, the hair can be dyed as it is human hair. But there is a general rule that hair can be dyed from lighter color to darker color. And we suggest you to ask the professional hair stylist to dye for you, Always try a small strand of hair when you dye it.
General Speaking the hair extensions can last for 2 to 4 months. The virgin hair could last at least 6 months (if you take good care of it, it can last for a year) Your personal care also matters the life of the extensions. In a word, the more you look after them the longer they will last.