Thank you for the update.
Your first photo is not fully drawn comb. Neither is the second, although it is pretty well-drawn. The third has a decent brood pattern, if the uncapped cells have eggs or larvae. I can't see that at the distance your photo was taken. The entrance looks nicely busy, but not crowded.
So my question to you is, does your existing box truly follow the 3 golden rules that you need to be true before adding another box?