All chicks are “she” until proven otherwise!

Important to know if your splash is a splash or a paint as they are very different genetically. Splash is part of BBS genetics and a paint has one copy of dominant white and one copy of black.
If you have a splash you can breed this one to a black and you will get blue silkies.
If your splash is a paint instead, bred with a black will also give you about 50% paint and 50% black.
Buff will add leakage to the other colors, which can be pretty, but will be difficult to breed out again.
If you breed the frizzled silkie to a regular silkie, half will be frizzled and half will be silkied, assuming that your frizzled has silkied type feathers (a sizzle) and not regular barbed feathers (frizzle) which would give a different result.