Sorry for the double post, but wanted to follow up:
Setting the VR Mode and changing around the values you suggested worked perfectly! The character is now running around and has its arms moving no problem. We also found that part of the problem was that there were two pawns being spawned, one ending up below the world for some strange reason. After deleting that, it solved the IK problem immediately.
We actually found that the problem was that we never set the VR Tracking Origin and it was set to floor level by default- we’re using a Vive, so we needed it to be Eye Level. By combining all these fixes, we have a working character with arm IK. Thank you so much for all your help, I really appreciate it!