I think I have some similar issue going on with my project. I started working with the spine plugin for ue4 (skeletal 2D animsation plugin) and it worked perfectly fine until I tired to package my project yesterday. I had some errors showing up that required me to update my plugin because they were using editor-only classes in the first version.
However, after updating the plugin UE4 required me to perform a rebuild for two .dll involved in the plugin. The automatic rebuild failed and asked me to perform a manual rebuild from source. When using the rebuild solution tool from VS2015 pro it comes up with an error such as "failed to produce item : “Project”/…/“Plugin.lib”.
I lack any programming skill so my project is full blueprint and to be honest I don’t understand like half the stuff that is going on in this thread. Yet it would be awesome is a solution could be released for this plugin packaging issue.
Best regards, Thom