I would look up some of the exterior landscaping from Palm Springs, CA, a very similar climate to Scottsdale, for inspiration. Keep drought-resistant plantings and use hardscape to your advantage. Here are a few inspo pics:

Skye in Palm Springs, California · More Info

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Thank you! I will look into Palm Springs, for sure.

@mojavemaria How much room would you ideally provide to an octopus agave? 48" deep planter, plants spaced about 6ft apart?

By a walkway, I wouldn't place any that poke and feel spiky.

As to height of foundation plants, and the 'walls' -- would this low wall work all the way across -with taller heights that are farther out into the yard.

Contemporary Moorpark · More Info

Personally, I like the slow walk to the entry to have interesting variety - there are nice mixes of succulents for that.

Contemporary Landscape - Dramatic Transformation - San Rafael, CA · More Info

Colorful succulents, such as these Echeveria 'Imbricata' and other low water plantings

probably Coral Reef Echeveria.

Terra cotta pots seem to cross styles well, whatever style of house.

Grace Design Associates · More Info

I suggest grouping that needs some shade. Malls and offices plant these aromatic white flowers which don't want hot sun. Nice fragrance for those nearby. Snow princess (lobularia) alyssum

Rancho Bernardo · More Info

Octopus agaves are not pokey, they have a terminal spike but its quite rubbery. I’ve never been hurt by one, wish i could say that for all my other agaves!

Since they only get about 3-4 ft wide i would space them closer than six feet. When they fully mature they flower and die so it would be best to get plants on the smaller size. Mine are actually babies from the flowering stalk of a plant at our previous house.

The trees will be feathery idk? I think for contrast, 'spiking' would be good out there with them... or another that contrasts a bit.