I don't see Jamo as expendable. He, along with Gibbs, has the most unique skillset on the entire Lions roster. If he indeed has improved his route running like the early returns in Training Camp indicate he has, he's going to be almost unstoppable. I don't think the cap is as tough to navigate as you think it is, these big contracts are on different timelines so as the new deals to the new wave of Jamo, Branch, Gibbs, LaPorta etc. kick in, the older contracts of Goff, Sewell, Kerby and ASRB will take up a lesser percentage of cap plus money can be pushed to later years etc. If Brad makes a splash move bringing in a guy from outside the organization, then the Lions will have to part with a core member or two but, as of now, I don't see why they have to dump Jamo because of supposed cap restraints.
The X Factor is Teslaa who I'm a big fan of but it's a big leap to think that he can replace what Jamo can bring but if IF he becomes like a Puca lite type then that gives the Lions options but, again, that's quite a stretch to expect that from him next season when the Jamo decision needs to be made