The rock looks good to me, seems to have a good number of cavelike niches in it.
Agree with Holly on the plants, though one other thing you might do in any case, whether you keep the ones in the foreground or not, is just to space them less evenly. The distances between the foreground and background ones are very orderly, might want to clump or stagger them for a more naturalistic look. You could wedge some of the foreground ones in between the rocks, too, as that's a common solution for keeping real plants with Africans given their digging habits.