Help with choosing breed to incubate?

My first suggestion is to go to this section on this forum and find your country or maybe a local thread. Then see if there are people near you that can provide the eggs you want instead of having them shipped. I’ve had some great hatch rates with shipped eggs but not so great is more of the rule. If you can find eggs local you can perhaps improve your hatch rate and see the parents of the eggs. Many people would like that.

https://www.backyardchickens.com/f/26/where-am-i-where-are-you

Which breed to get? That’s a real common question. From where you live one of the Sussex colors seems a natural choice. I don’t know how well the cockerels sell there but they will do well as meat birds. I’d suggest the Light Sussex since the white feathers give a prettier carcass when plucked compared to a darker bird, but another color might sell better. The Sussex should meet all your other criteria quite well. It does not sound like you are going to be trying to raise show birds, so it might be better to concentrate on meat as you are only talking about selling the cockerels.

A lot of other breeds will meet your criteria too. That’s part of what makes it so difficult, there are a lot of good choices. Any of the dual purpose breeds should fit your criteria pretty well.

Good luck!