I can see the benefits of broodies & incubator when they are time coordinated. Good idea. Also, the segregation of certain lines being isolated, then hen raised. Do you band the chicks to identify?
My hen hatched her 5 eggs late day , so tonight I will add this 5 day old single and watch. HOPING it will work & she will be a mom to 6.
I want to pen several hens with a roo for some of the reasons you have -- to define certain features. This is not as "in depth" as yours because they are hybrids but, I am looking to increase the egg color with my blue egg layers. So I want my pure lavender Ameraucana to cover about 10 blue layer hens. It will be a Spring hatch program as I have to "clean" the hens of other sperm, intro the roo, etc.
Ideally, broody hens will be used to slip these eggs under. And don't expect that in another month....maybe, but doubtful. 2 hens are brooding now but, the eggs I want to develop are not.

It would sure be nice if any wanted to set late summer, wouldn't it? -- pushing my luck. Never know. That would give me pullets laying Spring...a chance to view the experiment sooner than expected.
Today, I'm just thankful for the 5 eggs hatche & saved from Mr dead snake!! Life is good.