I really think with your experience you don't need to focus on just one project at a time. Focusing on one breed is for the inexperienced chicken breeder. I also think you could realistically move your timeline for the Jaded Amethyst Devil pot scrubber soup legs up to 3 years to completion.
Also, since you're planning on a rainbow of eggs I think you should incorporate that into the leghorns as well. What do you think you'll sell eggs for? $500 a dozen is fair I think. A proven broody, chess playing rooster I think you could easily ask $2000, maybe $3000.
But definitely don't just focus on one breed, definitely not time consuming enough.