Blue will let you get splash chicks, yes. When crossing a blue chicken to a splash chicken, you will get 50% blue offspring and 50% splash offspring.
When crossing a chocolate rooster with a splash hen, you will end up getting sexlinked chicks since the chocolate gene is on a sex chromosome. All of the male chicks will be blue split to chocolate while all of the pullets will be mauve. This doesn't help you get any splash chicks, but it would produce interesting colors and sexlinks which is nice. If you really wanted splash chicks and to also include the chocolate gene, them I would suggest a mauve rooster. That would give you 50% blue and 50% splash split to chocolate cockerels and 50% mauve and 50% chocolate splash pullets.