So, I can only answer a couple of those, which I will address in reverse order.
4) "All-Flock". or "Flock Raiser". Both alternate names for substantially the same thing - a generic poultry feed that's good for a lot of things, not great at anything, and also not dangerous too anything. Its moderately high in protein, good for growing birds of all sorts, and meaties and game particularly, but not so high as to potentially encourage angel wing in ducks, geese, and related species. It has calcium for bone growth, not enough to support layers, but not so much as to damage the kidneys of all the males, and any not laying, particularly in formative months. It should be higher in certain trace minerals, like niacin, than a similar protein percentage pure chicken feed, for the benefit of species that need it. Though it being a trace mineral, the differences are quite small.
3) I'll defer to others here.
2) If you are selling them, its up to the buyer what is done with them - once sold, they are beyond your control. You can't guarantee they will be kept as pets, layers, etc. Where to sell them will depend on your location and your neighbors. FB Marketplace. Craig's list. You may have a local "Green sheet". Farmer's markets/community swaps. A pin up board at the local ag extension. The local Buy/Sell/Swap threads here at BYC. Where you choose to advertise will help to alter the nature of your buyers. A mention at the local PTA that you have baby chicks available for purchase is a different crowd than the Saturday farmer's market - and the uptown organic produce market is likely different crowd than the market outside the county farmer's coop.
1) Not me. I prefer greater certainty, as my resources are limited and my needs are specific.
