Do it.
You will then have 4 dominant down lineman. Can always rotate a fresh one in when playing only 3. If the need for 4 comes up, there you go.
Secondary is addressed.
Linebackers, maybe some depth would be good.
Don't really have a need anywhere else. Maybe on the OL. Could maybe use a WR.
Take Billings in the 4th. If he does have a bad knee, well it was a 4th and nothing else needed to really be addressed anyway.
If he pans out, look out.