Your understanding is correct: an RPI is intended for a single medicinal product/development, including fixed-dose combination products (FDCs). It is thus possible in IRIS to select more than one SMS substance when requesting a new RPI.
However, for separate products to be co-administered, or for so-called combination packs, separate RPIs should be requested.
There is no need for the requester to provide a "product name" to relate to the requested RPI: the name of the RPI is simply the name of the active substance, or the concatenation of the active substances in alphabetical order (if more than one).
Finally, there are currently no plans to make the list of EMA RPIs public.