Since you're in Hawaii, I'd think a natural choice would be a mixture of both deep red and variegated pink/cream/red/light green ti (Cordyline fruticosa). They can be decapitated to propagate, and the stumps rejuventate to lower their heights.

White Candles (Whitfieldia elongata) flowers in white on glossy green leaves in very little sun. Grows to 6'

I was out pruning today, and it dawned on me that perhaps many of the cane or cane-like shrub begonias would be great in your predicament.

Begonia aconitifolia or B. reniformis or the very flowery B. coccinea, B. valida. Attractive leaves and flushes of flowers, and your spot seems to have jsut enough direct sun to encourage flowering without burning leaves.

I thought about ti but wanted more of a leaf shape contrast with the lily. Begonia might be very nice however, maybe even a mix a few of the rounder leaved ti in towards the back...thanks