I think there is some kind of bond, not Nahel for sure, and also not Luhel. I'd be shocked if those are the only two possible bonds though. I like Treamayne's idea of an "Emotion" bond.
Could you provide some examples of hints towards Endowment changing Awakening? Awakening is a general principle (I think) that just happens to be easier to do with Breaths than most Investiture.
I see this as an example of a different power system that can Awaken. I believe there is a WOB more directly answering it, but I couldn't find it. If I'm right about that, I don't think Endowment could change a fundamental aspect of the entire cosmere.