Is the creation of Skaze end-negative?
So, you're not quite using the term right.
The terms "End negative" and "End positive" refer to a specific system--in most cases, we're talking about the individual(s) using the magic. Do you draw more magic out, or is it powered by your own native investiture?
Awakening is what we call end neutral, despite the fact that (obviously) the Breaths came from someone else in the first place. That's not the point in contention here--do the same number of breaths (the same amount of investiture) continue to exist in the system as you're manipulating the magic.
In something like AonDor, you are drawing out much more power than you put in--end positive. That power is put to work doing something, such as healing a body, or creating a blast of power.
The Skaze, like the Seons, were created when a Shard was splintered. The terminology doesn't quite work there, at least not in the way that scholars in the cosmere would use it.
The question from the physicist in this thread about where investiture goes, and what it means for a shard to have access to certain amounts of power, is related to all of this. I'm hoping to be able to find some time to craft a response there, as there are some fundamental understandings of the magic that are relevant to the discussion that i should point out.