Emily, with being a renter, I'd definitely check Pinterest for temporary solutions. I've seen DIYs where you can starch fabric to walls with an iron. Also try temporary wall paper/decals, but I'd test a small area first. Cabinet makers or even yourself would be able to create a flush vanity without attaching it to the wall. Plywood, especially hoop pine, has received a lot of traction. It really gives a clean, organic look that you could have custom cut to fit in the area. You could also use it on the wall – it could be stained, left natural, or painted for a feature. Have a look at EchoPanel. It is a decorative, acoustic pinboard that would add a splash of color/design. If it is above your vanity, you could pin pictures, inspirations, etc.

I love the option to work in a private office while still feeling connected to the larger open plan space. And who doesn't want a huge blackboard to creatively brainstorm?

You have a large open area that could benefit from a little more zoning starting with the bbq and undercover area. If you could build in the bbq and add some bench seating which overlooks the back yard and add some vertical planters for herbs or succulents to separate this area. Zones create interest and you may enjoy the separation from the play areas while still maintaining supervision. Plants along the fence could certainly be a variety of lilly pilly or what about some citrus trees like limes for the cocktails, lemons for the salad dressing etc? Raised vegie gardens? A feature tree would be nice too but not sure what suits your area. Magnolias are very beautiful and the flowers are divine!

I really can't stand the word mindfullness. It's like wellbeing - just combining two words to make a new one feels so clunky. How about being conscious, aware, present, in the moment. I voted for #3, as i appreciate fresh air and natural light more than silence or seclusion. I dont have a space like this at the moment, but maybe a stool in my courtyard could do the trick. Thanks for the inspiration!