My friend is on Xbox One
I am using both Windows 10 and Xbox One.
I have encountered this issue in these configurations:

• My Win10 connecting to friend's Xbox
• My Xbox connecting to friend's Xbox
• Friend's Xbox connecting to my Xbox

In all cases, everything works fine for the host. The remote player will connect and spawn just fine. They can move around, their tamed wolves will follow them and attack mobs. They cannot pickup any dropped items. When they mine, their arm animates, but the block does not animate. The block still disappears after the appropriate amount of time on both host and remote screens, but there is no item dropped. If the remote player steps into the mined out blocks, everything will appear normal for them, but the host will be told they suffocated in a wall.