Hugelkultur in general will promote a better plant (grass/veggie/tree).
However The smaller they are the more Nitrogen they will use and so for the 1st year or so it might preform worse.
I am not too sure if placing
water storage amendment around your foundation is such a good idea, even if it will elevate the area.
I would just
compost the twig/mulch and then use the compost in the grass area.
It would settle even thus easier to maintain and it would make the grass "greener" and hold less water next to your foundation.
I would use the hugelkultur for the "NATIVES" that you want to plant.
With the mulch on top it will look better and more landscaped.
It seem that you partially doing this to increase the re-sale value so I would add some flowers too. Cheap grill, maybe some
solar light. A shade cloth/grape vine arbor/trellis patio. Not too sure what the kiddos would like.