Conflation of 3rd Party Data to Local OSM Planet Database (PostgreSQL)

I am seeking advice for a workflow solution to accomplish the conflation of 3rd party (e.g., government/private) data (.shp) into a local PostgreSQL/PostGIS database of the entire planet running on an in-house server.

I have become fluent with applying daily OSM changesets using Osmosis and Osm2pgsql. I am currently keeping our database up to date by appending the daily .osc changefiles to the database. This is working great, and I am comfortable with the osm2pgsql --append command.

In my initial research for available conflation methodologies/tools (e.g., JOSM, Hootenany), it looks like these tools do a great job at conflation with manual review of conflicts in a GUI environment (this is what we want!) but then they just upload the changesets directly to OSM servers to update the public map.

In our project, we will be working with sensitive/confidential data that absolutely cannot go public. Hence, our local planetary OSM Postgres server, and the need to produce a local changefile for appending vs. an OSM.org changeset upload.

Is it currently possible with any existing tooling to conflate to/compare against a local PostgreSQL database on the planetary scale, and after conflating/conflict resolution, locally export a standard changefile that would go through the normal osm2pgsql --append process, like applying a daily diff?