The last boy looks to be an EE. Good layers, decent meat birds (course depends the mix)
First boy looks the meatiest
If you can seperate them into 3 pens, each with about 4-5 hens, common ancestry and same breed, then incubate from each pen, you'll get a good idea of what they'll throw in terms of meat or eggs. Keep the boy who won't overbreed your hens, not aggressive to you, but also throws good layers and meaty boys. Personally, if you have enough hens it'd be better for you to keep all 3. That way you can keep the boy who throws meaty boys, the boy who'll throw good layers, and then the one who throws fast growers... If they don't have any good genes, or 2 of them throw bad layers but good meaty ones, then keep the more docile one or prettier one.
A good, diverse flock is the best possible thing you can get. You just need to be able to find who throws what, and if their worthy keeping