QB - It is what it is. Gotta see Mitch through and I think with his recent play has earned the opportunity. Need a different backup, but have to be cost effective about it.
RB - Maybe spend one of your three 5th rounders on one? Montgomery has looked really good and Cohen is your gadget guy. Can also add someone in free agency fairly cheap as the position has become less of a priority.
RE - Robinson is under contract, but I'd make all efforts to extend him. He's a top 10 talent. Outside of that the group isn't bad. You do need that #1 and continuing to get developmental players might be the most cost effective way to operate.
TE - I disagree with needing someone. Run with Horsted and Holtz and draft someone in the later rounds to compete. Hooper is 'fine', but he'd probably cost over $5m/year. There's no need to commit any more cap space or draft capital to the position. Kelce is by far and away the best TE and he's a 3rd rounder. Gronk was a 2nd. Kittle was a 5th rounder. Run with what you have and take a swing at a later pick and develop them. With the team having limited cap space, some contracts coming due (Mitch and Robinson) there's no need to do more here.
OT - Here's where you might have to spend some money and draft at least one person. There's a lot of sub 30 year old names coming due. Maybe sign 2? The biggest issue with this position group is the current guys aren't tradable assets and there is only a small amount of cap space created by cutting Leno (Massie actually costs an extra $3.8M to cut).
OG - You are decent here. Not much depth, so maybe some tinkering can help provide options. Long will be gone which is good for the cap.
C - Leave it alone. Whitehair is probably your guy with Daniels being able to help in a pinch.