The shrubs against the house are Pieris, Ilex on the corner, Dwarf Rhodendron in front if the Pieris.
Hostas will work. There are many varieties to chose from with many different heights and spreads as well as many colors. Just keep in mind that deer love Hosta. Also Hosta die back in the winter so the area will be bare a few months a year.

This project is amazing; I admire your talent. Did you steel edging to hold back the gravel where there is no wall? I am looking for an inexpensive way to hold back the gravel along my long driveway. I plan to put in a few low walls like the one pictured above, but I can't afford to line the entire driveway. I am hoping to get a similar effect with less expensive stone. Thank you!

You can use steel but I used a stone curbing on this project