I am happy you got it working. This thread shows the entire purpose of the AEM community.

We do not have any use case or docs that describe how to overwrite the editor.html page in this manner.

A nested multifield has a specific node pattern for the dialog. I recommend that you look here for that pattern. It has an outer and then inner pattern - as discussed here: Experiencing Adobe Experience Manager - Day CQ: AEM 64 - Touch UI Nested Composite Multifield Using Coral 3 Now you can query f...

Are you using a custom workflow step that uses Java code or an OOTB step?

What are you trying to do here - if you get a result set of certain components - what are you going to do with the data?

Is this API what you are referring to? "The Adobe AEM Quickstart and Web Application."

Yes - we have many AEM HELPX articles on how to create a custom workflow step. Start with this one on how to create a custom workflow step and work with Assets via the AssetManager API:Modifying Digital Assets using Adobe Experience Manager WorkflowsThis will teach you how to work with the various A...

What AEM Version are on you using? IPArsys was used to make static templates have a common look and feel (for example - common components on all pages of the web site with the same data on each - like footer and headers).IN AEM 6.4 - you should not be using that anymore for that purpose. You should ...

"Do I need to create a custom workflow which somehow handles that" - the answer is yes. That would be the only way for this requirement.

AEM is a platform and you can build a lot of different pieces using custom components.