Difficult to choose between them.
I think the steps on the first one would make nice planting areas, so I think that's the one I would go for.
But don't stop there, can we have some more designs please? It's nice looking at them, just wish I could play in your sand pit too!
I like them as well. The last one the most I think.
To give you some critique I think the hardscape could benefit with a pathway from the opening midt front (maybe force it a bit more left) with a slope up to rocks just behind, and from there zig sack trough the rocks to the back. This might give a clear endpoint for you scape.
I think allso some more height at the back RH and LH corners would please my eyes. Mabe driftwood or some more rock.