Hi Daniel,
Sounds good. Yes, most of it should work with 5.6.3 (and maybe 5.5.1) already. We just added better documentation for 6.0.
Also, “creating and publishing custom components” would be even cleaner for you I think. You just need to do that within a plugin to inject the factory. But if you already write your own plugin then you should definitely try it.
Also with the java component you have some things preconfigured that are bound to the java-library configuration/variants (implementation, api, runtimeOnly, …).
If you define your own component, you can set everything up from scratch using configurations as you please. You can also use the configurations provided by the war plugin to build up the new component. In that case, you might not even need the java-library plugin.
And if you end up with a working component setup, feel free to post here. We might be interested to promote that into the war plugin. 