It won't require a 3rd team.
It's unlikely DeBrincat and Zub both re-sign at this point. Could see one staying (hopefully Zub) but both is doubtful.
ADB was always going to be a longshot to stay.
The Sens not even discussing an extension with him pre-trade says a lot. He's an American that has played his whole career in his home country and wasn't thrilled to come here initially. Not sure the performance of the team thus far has changed that.
The lack of negotiations with Zub's camp is as worrisome as it is headscratching. Absolutely need him to stay and if he decides to bolt for greener pastures our need for a RD will be even bigger than it is now. JBD would be our top RD at that point