There's no need to "count on" anything for now. The flows for Compass and Mesaba are intact, unless the JCBA doesn't pass. The flow is part of the JCBA.
Now, things can happen, of course. Compass or Mesaba could be sold off, and then things become less clear. I understand there is language about the flow being transferable, but time alone would tell how it plays out in the real world.
Needless to say, in 4+ years, when a new contract happens, anything goes. However, if the JCBA passes, then the flow will be in effect for the next 4 years at least. If it's part of the JCBA, Delta won't simply be able to "change their mind" about it.