It's looking good. I think I'd lower the water level to 2", or, even easier add another inch of rocks to the deep part. You may need a larger area to one side for feeding. Both crickets and dubias will drown. Yes, you can feed them small crickets and dubias. Your calcium and vitamin schedule is right on. Another thing you can do is to make a small floating platform so the crickets crawl up it if they fall in and the toads can still get them. You can remove it when not in use.

We loved our firebellies . Are you getting greens or browns?