EMB-175 flight crew reported multiple avionics system failures in cruise flight. Diverted and landed uneventfully.

Narrative

In cruise AP (Autopilot) fail; AOA Limit fail; AT (autothrottles) fail; and all course guidance from FMS. Hand flying we had low speed cues; PLI (Pitch Limit Indicator); and subsequently stick shaker activation. Corrective action is trained to reduce pitch; consequently descending out of our assigned cruising altitude. Captain requested block altitude while we troubleshoot the problem. Stick shaker intermittently activating; we respected the indication and would periodically level and descend to satisfy the stall. We descended; leveled; and climbed all around our block altitude until we made the plan to land at the nearest suitable airport; which happened to be ZZZ. We now understood we never had been aerodynamically stalled and we were receiving false indications. Center gave us delay vectors while we made our plan; communicated with our crew and company; and subsequently gave us priority handling into ZZZ. We landed and completed our flight without any injuries. The cause of the malfunction is still under investigation. Corrective actions may include Embraer explicitly detailing a QRH procedure to deactivate Stick shaker associated with specific 'AOA Limit Fail' caution message; however that solution may also be a threat. The stick shaker activation proved to be distracting and insidious enough to prevent our crew from maintaining altitude; out of respect for the indicated stall. In IMC; and at lower cruise altitudes the loss we committed of 10;000' could result in descending below MEA and possibly interfering with traffic.