The color is Lavendar, and it looks to be an Orpington, but its beak is somewhat mottled, so it could be either a light-colored Lavender, a Cuckoo Lavender, or a Lavendar crossed with something else such as an Australorp. I have a couple of Buffs that were crossed with an Australorp that have the same mottled beak, and they also have some black leakage; that's what I mentioned that last option.
Have you had the chance to ask the breeder what it could be, and have you seen the birds that produced the chicks?
We have two lavender orps that look nearly identical to your chics. From same hatch but one had a major growth spurt and quickly surpassed the other in size. They were about 3 weeks old in these pics. They’re 7 weeks old now. Still unsure on their sexes. Trying to be patient. Not easy ....as we all know.