Non-vestibular Schwannoma

This is a multi-arm phase II platform-basket screening study designed to test multiple experimental therapies simultaneously in patients with NF2-related schwannomatosis (NF2-SWN, formerly known as neurofibromatosis type 2) with associated progressive tumors of vestibular schwannomas (VS), non-vestibular schwannomas (non-VS), meningiomas, and ependymomas. This Master Study is being conducted as a "basket" study that may allow people with multiple tumor types associated with NF2-SWN to receive new drugs throughout this study. Embedded within the Master Study are individual drug substudies. * Investigational Drug Sub-study A: Brigatinib * Investigational Drug Sub-study B: Neratinib * Investigational Drug Sub-study C: Retifanlimab plus bevacizumab