Wardian case - White Garden - Plant selection

As one of my apprentice projects at Otari I need to select some plants to be displayed in the Wardian case, write some info about the plants, and look after them.

I got my inspration for a white garden from both my recent visit to Sissinghurst, but also from watering the Celmisia collection in the nursery. I initially thought about displaying the celmisia collection until I found out it had already been done.
So I started noticing just how many plants in Otari have silvery foliage or white flowers - a heck of a lot, so I had plenty of choice of plants to create my own White Garden.

After some research and plant identification I selected the plants I wanted from the nursery...

Astelia nervosa. Silvery and stripy. 

Euphorbia glauca. Very pale and interesting.

Hebe albicans. Because I couldn't not use a hebe!

Pimelea prostrata. Low wide spread groundcover. I more I see
this plant, the more I like it.

Pacystegia insignis. Awesome thick dark green leaves with white
 undersides. Only downside is that the center of the flower is yellow
...but I like it soo much, so i'm gonna use it anyway.

My initial collection - still slightly undecided on which climber
I want, and small tree.