I ordered the zone offroad 4.5" lift with full leaf packs. I was wondering if the lower control arms that come with the kit will work with control arm drop brackets

They said the arms were 16.25". What is the stock length

stock lca's are 15.75"

At 4-4.5" lift, with CAD brackets, arms should be about stock length. So I would say that the new lowers you have will push the axle forward with the brackets.
I believe on the Yucca Man website he has a chart of approx lengths.

So would my axle be pushed farther forward than stock with the CAD or will the axle be in the stock location with the CAD