Win 10 Bedrock 1.7.1 is unable to local multiplayer with mobile Bedrock 1.7.0, either as server or client (neither way will show the other in friends list - and yes, both logged into xbox live), presumably because mobile Bedrock is "stuck" at 1.7.0 (ie, did not receive the 1.7.1 hotfix that was targeted only at Win10/Xbox).  With local multiplayer being so dependent on exact version matches, any "targeted" hotfix release will likely pose ongoing problems.  Need to get the versions synced up again, and keep them synced in the future.