Some clarification on Fontecchio and his free agent status this summer.
Yes he is restricted meaning Detroit can match any offers. But no, they can't go over the cap to sign him. At least not the normal way.
He is an early Bird rights player. That means they can go over the cap to sign him, but it isn't unlimited like normal Bird rights players. Early Bird you can go up to 175% of this years contract or 105% of the league average, whichever is larger.
His contract this season is about $3m so they could offer just over $5m. The league average salary is around $8m so that will be the max they can offer without using cap space. Anything over that and they must have free cap space to sign him. Which is fine since they are projected to have almost $60m in cap space.