I see the tree as a living thing that took years to grow so I do understand the outrage, for lack of a better word. I see the house as made of wood, brick, mortar etc... It takes years to grow the tress to make the wood though...
The landlord can rebuild the house better than before and have the Church come in and bless the home. I understand that a lot of people will not live in a home where somebody has died but I also believe there are many who will, even to the point of having the home blessed again by their own minister. Then, there are others who it will not matter to at all as long as the home is nice and worth the asking/rental price. It took a couple of months but HaLeighs home rented. People move on, life goes on, I think Zahra would want it that way.
I think the idea of planting a tree with a marker for her in an already established Park is a great idea though! Or... a special children's flower/vegetable garden, maintained by the local Gardening Club etc, where children could go and learn to garden and take home a few flowers to their own families as well. I guess I just think it is better to do something like that off site and on untainted ground if you will. JMO