I'd wait till it feathers out.
Could be a Splash chick, but could be something else as well. Looks both White, & yellow with some black. Haven't seen that with Wheaten chicks.
There's two white genes, Dominant White(Shows with 1-2 copies), & Recessive White(Needs both parents with a copy to express).
Then there's Silver, a different gene that makes white birds.
The hen is Blue Buff(Columbian)in color, most likely Wheaten based. Both are Dominant.
Lavender would act as black, that's correct if he were the father, so the mother would make either leaky black, or blue Incomplete Columbian chicks.
That hen, & Blue Copper Marans would produce Blue, Black...