geofelt :
Any Z270 based motherboard will do the job.
Higher priced motherboards will have options such as premium sound, sli capability and record seeking overclock options such as ln2 capability and monitoring points.
I would avoid sli options. GTX1080 is more than enough for gaming at 1080P
Be sure to register your EVGA card. That gives you a better warranty and enables the free 90 day trade up option if you should decide to upgrade to a GTX1080ti. Read the fine print on their web site.
You might consider a smaller M-ATX size motherboard if you want a more compact case.
Well GTX1080 is enough. It depends even GTX1070 is enough to get 60fps+ but getting 60fps+ for now and getting it for a longer period of time are different matters. GTX1080Ti is giving 25% better fps at 1080p than GTX1080 so when you consider it on a long run GTX1080Ti is definitely a better option to go for.
Yes SLI is not important.
Case that is the best for that budget range. Going for smaller compact case also has drawbacks first the airflow. Second it is not easy to work with especially cable management is hard. Third good quality small form factor case costs more.