Statistically, looking at the amel and lav genes, and assuming the miami is not het amel...
You'd produce normals in the F1. They would be het for amel, and half of them would be het for lav.
Breeding these F1s to each other, you'd have a 1 in 4 chance of getting a pair that is also both het for lav. In that case, you'd get the standard 9:3:3:1 outcome of 9 normals, 3 amels, 3 lavs, and 1 opal. (statistically)
If none or one of the parents is het lav, you will only get normals and amels, in a 3:1 ratio.
So basically, the fact that the amel is het lav will probably not have a huge effect on your project.
However, realize that just because you are starting with an amel and a Miami, it doesn't mean you will have Candycanes in the F2. Ask anyone who has produced candycanes, and you will find out how much work it really is.
