IDs inconsistent when importing on a new system

I came here from https://github.com/elastic/kibana/pull/11632 looking for a way to export from one Kibana and import to another. The import using this tool to an empty (ie, there are no .kibana/saved_objects) elasticsearch runs okay, however it leaves the interlinking IDs inconsistent. Dashboards should point to visualizations, which point to searches, which point to indexes. All of those pointers ought be hooked up in the new elasticsearch. I'm in 5.6.4 for both, if that matters.

Is this understanding about right?

If so I can work on a fix, which might go like this (if also sounding about right?)
1. post all the saved searches from the loaded objects, recording their old and new IDs
2. post all the visualizations from the loaded objects, doing the mapping from (1), and recording old and new IDs.
3. post all the dashboards from the loaded objects, using the mapping from (2)