This fairly simple plugin adds a metadata set that allows for embedding Neatline exhibits in Item Pages. To add a Neatline exhibit to an item, go to the "Neatline Display" element set, and set the Neatline Exhibit to the slug of the exhibit you want to embed, and optionally add a record number, to display that record by default.
This plugin may not interact well with your exhibit, particularly if you have a Simile timeline or waypoints, as it may show up very small.
Additionally, I've used an Element set to make this happen, so by default the data used by the plugin shows up on the items/show page. I recommend suppressing this with the Hide Elements plugin, until the back end gets done properly.