Get a hotel registration # in Gewerberegister in Germany for the purpose of Schengen Visa application

This is a spillover question from How to apply for a German Schengen visa, staying in a small hotel with no registration #

I need to get a Schengen visa to stay in Germany for 6 nights in mid-Rhineland area (Koblenz and vicinity). In Schengen visa application, there is a section for "reference" (german Referenz (Angaben zu einladender Person/Institution)), where you are supposed to put your hotel name, registry name (Name des Registers der Organisation) and number the hotel has in this particular registry (Registernummer). The registries proposed in the VIDEX form are:

1. Gewerberegister
2. Handelsregister
3. Partnerschaftsregister
4. Vereinsregister 5 Genossenschaftsregister
5. Sonstige deutsche oder ausländische Register (other register)

I contacted 5 hotels in the area that I liked with the question:

Please provide me your registration number in Gewerberegister

One of them replied:

as singleowner of a Hotel are we not registered in the Gewerberegister

the others seemed to silently ignore my question.

Questions:

1. My understanding that almost every income producing entity has to be registered in Gewerberegister. How do I find this number for a hotel that I like?
2. How do I locate a hotel that is willing to share this number? How do I even start to search for that?
3. Is it possible to apply and successfully receive the visa if I do not know the hotel Gewerberegister (or other registers) number?