1. Yes, also applicable to the WINNER2 channel model, however note that in the demo only linear arrays are assumed, you can check in the code if WINNER supports the elevation dimension.
2. The horizontal separation only determines how correlated the channels are from different ports, since there is no connection between elements horizontally. However, it is possible to define antenna arrays where you connect several element horizontally in one port, but we don’t support that currently.
3. If the distance between the adjacent elements is equal or less than the wavelength, linear antenna array has only one beam peak within the visible observation angle region (-90° –90°). When this distance is larger than one wavelength, the unwanted beam peak (grating lobe) occurs in the real angle range of (-90° –90°). Therefore, observation angle range dictates the value of the maximum element spacing to avoid the occurrence of the grating lobe.
To understand how this works, I recommend the following material where this is explained: https://owncloud.nt.tuwien.ac.at/index.php/s/Zw1nol4pHCpOuKj
To access the link, use the password: lte