Bears have about 15m in cap space, can probably free up another 5+ with restructures.
There is room to sign another ILB, G and SS without even cutting anyone. They may just be competition level on defense. I think they need a legit guard through the draft or FA. That should probably the main focus.
I think Bush can compete at SS with someone brought in.
ILB is a different story....It could go bad here if they don't have a solid performer. If they can bring back Trev and JPL within reason it is probably the right thing to do.