Installing PostGIS in a different schema causes topology extension to not find geometry type
The reason for the schema move is that we are using database schemas to isolate data for multiple tenants. Thus, public will not always be in the search path. By moving PostGIS to its own schema, we can keep that in the search path at all times


Good luck with that. It's no longer possible in new versions of PostGIS, including 2.4.2 r16113 -- the version you're using. From the site,


  As of PostGIS 2.3, the postgis extension was changed to no longer allow relocation. All function calls within the extension are now schema qualified.


You'll have to install it into public, and then move it. YMMV. It's not supported. Again, from the official site,

UPDATE pg_extension 
  SET extrelocatable = TRUE 
    WHERE extname = 'postgis';

ALTER EXTENSION postgis 
  SET SCHEMA postgis;

ALTER EXTENSION postgis 
  UPDATE TO "2.4.1next";

ALTER EXTENSION postgis 
  UPDATE TO "2.4.1";