Hi everyone! I am so excited to finally start my gardening and backyard landscaping. I am from the east but have been here for 10 years. I LOVE trees. I miss them so much. I have a somewhat large backyard (for las vegas) and have to pick out a few trees. One I need to plant toward the back corner of my yard in about about 23 x 20 foot triangle area (yard ends in a point) and one fence borders my neighbors yard. My neighbor has a pool and so I don't want a tree that is going to litter constantly or overgrow the area. But I do want a NICE big shade tree for my dog because that is his area. I am trying to find the right balance. I love weeping trees and I want to sort of do a nice weepy romantic yard. Trees I am deciding between are;

Weeping Acacia - is it hardy enough? how much litter? Good shade?

Eucalpytus Microtheca aka coolibah - adore this tree, it seems to be great but how can I get a good wide shade area? anyone have problems with this specific tree?

Thornless Honey Mesquitte (called maverick) - Looks pretty in some photos but I am not sure if it is actually just depending on the specimen. Problems?

Because the wall will be surrounding the tree on two sides East and west it should be fairly protected from the wind.

Lastly I want to plant 2 Acacia shoestrings by my patio area

I love these trees when they are full and large but I want to know how I can make sure they are full.

When should I plant my trees? I was told differently by two arborists! One said in the fall would be fine and one said it was a risk in my area (centennial) to plant in the fall in case we had a bad winter. Seems to me our winters have been very mild that past 10 years so I don't know if it would be a problem.

Lastly I am somewhat open to suggestions but I do recognize ALL trees have problems.
I have ruled out african sumac because its high litter.
Not sure about Ash trees. I haven't seen one in person that WOWS ME.

THANK YOU!!