Please read through the Outdoor MIMO VRD thoroughly as it covers many of these and likely future questions.
http://community.arubanetworks.com/t5/Validated-Reference-Design/Outdoor-MIMO-Wireless-Networks/ta-p/155624
The ANT-90 is designed for client coverage only as a downtilt omnidirectional antenna, and is not designed for use as a mesh antenna. It was replaced by the ANT-3x3-D100, which is a directional 100deg x 90deg and can be used as a directional client access or mesh antenna when used in the H-Plane (facing out), or as a client access only antenna in a down-tilt orientation (facing down) and is not recommended for mesh).
As far as doing client access and mesh on the same radios, that is not recommended, but if performance of the mesh is not critical and you don't care about bandwidth andor latency, you can.
As a partner, you have access to the partner portal on arubapedia, as well as all the public VRDs.