GeoFabrik's extracts - as expected - have a massive amount of unnecessary information for most applications. Filtering this information is a critical step to decrease the map's size, especially for mobile uses. OsmFilter or Osmium seem to be the main tools for the job, however, the list of nodes, lines and so on in OSM is simply overwhelming. Could one method simply be retrieving the used named layers in Mapbox Strets v7 (for example), and remove everything else?
On a side note, it seems that converting tags might be necessary, is there any comprehensive list/guide on these subjects?