First off, don't believe 18awg claims on Chinese stuff including pixels from Ray. Ray has admitted his pixels are not 18AWG (too big for boards). His...
Ip65 under the eaves, out of the weather will probably be ok. But given the choice I would go with the IP68, especially for a permanent installation....
I tried, but I honestly don't have any suggestions. I thought of maybe trying LED strips, because your display is basically 2-dimensional and that's...