I would put rocks around the trees you wanted to grow between the houses... fast growing evergreens. We planted 2 Blue Ice Arizona Cypress Trees just 3 years ago and they are GIANT! They are about 7 1/2' wide by 10' high. Very pretty grey blue too. Whispy.. they were about 1' high when we got them. Cost was about $9. each. I don't have "neighbor problems" they just look great & grow real FAST!
If could put rocks around them to protect them from the neighbors cars. < The larger the rocks the better!