I don't know if these points are bugs or misunderstandings, but wanted to clarify things...
Admin / GetStoreItems
You should add in the documentation that CatalogVersion is required in the parameters. If ommited or wrong, always returns empty array.
Admin / GetRandomResultTables
Also, the main CatalogVersion seems required in the parameters to get accurate results. If not set, there is a return, but not corresponding to the dashboard values. So it seems that drop tables are linked to a catalog, which is not seen on the dashboard. Weird.
Deletions
=> It's possible to delete a store, but not catalogs, currencies or drop tables. There is no way to clean up things except create a new title...
Admin / Create Drop Table
=> From admin APIs, it's possible to create a store, but not a drop table. A "SetRandomResultTable" API would be consistent (and useful).
Server / GetStoreItems
=> Already asked, but just a reminder to be able to get store prices from cloudscript