HI Mikhail,
Nice plans, if you are looking forward to use the jbpm console ng it would be nice if you share your thoughts and ideas about which requirements do you currently have or expect from it. So we can make sure to implement what is expected.
About the two plans..
The plan 1 sounds more appropriate to me, you don't need to mess with the console if you are not using it. The services which are inside the console backend are console specific, if you use the HT module alone you can tweak it for your special use case. You should take a look at our rest integration: https://github.com/droolsjbpm/droolsjbpm-integration/tree/master/kie-remote/kie-services-remote
Take a look at that and if you have feedback we can improve that as well, There is no need to re invent the wheel, we should all collaborate to get these kind of things to work for everyone.
Cheers