If the drops of blood are very few and this does not happen every month, but it happens sometimes and it is not pure blood but is yellowish or brownish, then this does not count as anything and you do not have to repeat the ghusl.

It is not permissible not to wash your hair during ghusl after sexual intercourse or periods. Therefore, you have to repeat the prayer. If your hair is braided, then it is sufficient to pour water over it thrice.

A husband cannot have intercourse with his wife in the vagina when she is menstruating or in nifas. But he can be intimate by kissing, embracing, touching etc., parts that are above the navel and below the knee. Scholars differed on being intimate with regard to the area between the navel and the knee, apart from the front or back passage.