The first step is solving your CC 2015 AddOn problem in general. I think if you can get a clean installation of Dreamweaver that allows you to install the Server Behaviors and Database extension from Adobe then installing DataBridge wouldn't be an issue.
You aren't really having an issue with Data Bridge installing, you are having an issue with Dreamweaver in general that you are continuing to experience after installing DataBridge.
You would still have all of these errors without ever installing DataBridge at all. We have to fix the errors before installing DataBridge before installing DataBridge because that is just compounding and adding complexity to the issue.
I think the node error is another red herring and a symptom more than it is the issue. You get that with the DMXZone extension manager, but I have a feeling it too is just happening because of a core issue with your Dreamweaver installation itself.
If I were you I would work on:
1) Getting a clean installation of CC 2015 that doesn't error
2) Making sure you can then install the Server Behaviors and Database extension from Adobe
I think if you can get to that point you won't have an issue with webassist extensions or the DMXZone extension manager because Dreamweaver will be functioning properly to begin with. But if you aren't to that point then you will continue to have issues with any addons or programs that work with Dreamweaver as well.