It depends on what the single gene is and what the goal you are working toward is. Some single gene animals command decent prices because they are either highly in demand, or rare, or both. YB is one of those morphs that there are thousands of for sale on the market, so by itself, it's a tough sale and cheap. Breeding a YB female to lets say your Lesser male, still wouldn't be an ideal pairing, but at least it is working towards stacking up new morphs in the project, even if they all sell cheap. YB to Asphalt, so you get your Freeway, but then to add anything else, you are back to a clutch of Asphalt/YB's possibly in combo with the new morph you are trying to add.

You don't want to go too crazy breeding 5+ morph to 5+ morph, because then it is a nightmare to identify and you end up selling many of them as a couple of those morphs "poss" the rest.

You have some great animals there, with a lot of potential, and there are a few combinations I would think are great pairings to get started with. Some of those animals, I would seek out something slightly different from the mates you have available. You are pretty male heavy right now, so I would probably focus on the next couple of purchases being female, and have female-heavy holdbacks. I would make that Banana Clown male the star of your show for right now. He would be a great choice to breed your YB female to if he is ready to go! You would get no visual Clowns, but Banana on it's own sell pretty well, Banana YB even better, and you hold back one female YB het Clown and bring that project to the next level with what YB adds to both Clown and Banana when she is up to size and can be bred back to the sire.

If you want to tell me which males are up to size if the Banana Clown isn't, I could make a different suggestion.