SPFx solution with 2 pages and web parts communicating

I am replacing a server side solution that allowed a master application page to fire headless window that talk to the originating page.

Now I am doing it in SPO with SPFx and so far I just used one page and web part with a big dialog that can't get out of the sending page.

My users want to be able to put the dialog on the second monitor so I think I have to do it in a different window / web part. I am planning a version 2.0 and collection ideas how to do it.

So far I think I will use "https://www.npmjs.com/package/broadcast-channel" for communicating between the parent page/web part and the child page/web part.

I still need to figure out the following:

1. How to create a sharepoint page containing just a SPFx web part without all the side and top bla bla. (safe to hide by CSS?)
2. How to pass the spfxContext from parent to child 
3. how to debug 2 separate SPFx projects at the same time while building the solution.

Any suggestion is welcomed. Samples even more 😘 

Thank you in advance.