I live in some rolling hills. would it be a problem to mount my equipment at 400ft or even 500ft so that it is easier to get line of sight from more places?
You could do that, but be sure to apply appropriate downtilt. You can put in your customer locations or at least a sampling of customer locations and run the "Calc Tilt" in LINKPlanner to determine the best tilt to serve the customer base. There's already 2 degrees of built in electrical downtilt for the 4x4 MU-MIMO antenna, but this is accounted for in LINKPlanner so the tilt it gives you is the actual physical tilt.
SInce this will exceed the 100m limit of Cat5 you'll need to run fiber to the SFP port of the e3k for data. I'd also test the PoE over that distance prior to installation to ensure sufficient voltage and power can still be provided to the e3k form your power supply over that distance. You can just terminate the ends on the reel you plan on using and test it to ensure that it can work over that distance.