if you can get a cockerel that looks like the first 2 cochins that would be the best for those 2. a black can be used with the splash as well as blue o another splash. with the millie i would use another milli. but if you just want one go with a black cochin most of the offsping will be black...
the first 2 are slightly barred making them blue barred cochin
looks like either a blue mottled or a splash cochin, a red sex link and a milli cochin
looks like it maybe an assui and the white might be a white wyandotte or a mix