> is there a proper trail to Wotans Throne from MWT or MR?

No. You just hike up and around WT, off trail. The northwest side is third class. You can descend from that approach down to Mirror Lake, but it is ugly steep.

Pinnacle Ridge lies between WT and the Mountaineers Route. I have never heard of anyone crossing it. It is definitely accessible on the south side, but the north side not so much.