Sorry to hear of your loss.* I too have recently lost 2 beloved dogs so I can understand your desire to do this.
You don't say where you live, but from the temperature you mention (112*F), I'm thinking you are in the Southern Hemisphere, possibly in a desert climate.* Without info on where you live, the sun conditions of the area you wish to plant, the type of soil you have, the type of climate as to dry or wet and how much space you have, it would be impossible to make specific plant recommendations.
Many people plant white flowers as a memorial garden.
I've never heard of mirrors attracting wasps, at least not the ones here in the US.* Wasps are attracted to sugar and sweet food.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.