I don't know much about OEGB genetics, but I would guess yes, *if* they are all pure bred, and not crosses back a generation or two. A bird can look pure but still have traits that will pop up in their offspring. Hopefully someone else will have a definitive answer for you!
No. Self blue is not related to regular blue. If you had a blue (not a self blue, aka lavender) then you'd get 50% blue red, 50% black breasted red.
But self blue is a recessive gene, so you'd have to breed back to it twice before the babies would start having some lavander. But it'd mess up your coloring pretty badly anyway, since it's a solid color being bred to a more patterned variety.