If it were me, I wouldn't even kick the tires on Grubauer. The Red Wings shouldn't be trading future assets for a gamble in net, and to keep Grubauer past the next season it'll probably take money and term that he may not eventually live up to.
I'd look into Hutton, but only if the money/term makes sense. The guy turns 33 in December, so any more than 2 years is pushing it for a guy that is likely going to cost somewhere right in between the average #2 and #1 salary. I'd walk away if it takes giving more term or money to outbid teams trying to make him their #1 for next season.
Given that they aren't trying to really compete next season, the Red Wings don't need goaltending, so I'd approach it like this:
-Let Coreau and McCollum walk
-Sign a couple of fringe guys like Andrew Hammond, Scott Wedgewood, Harri Sateri etc. etc. for around $800k for a year
-Then the two of them and Rybar battle it out in camp and the pre-season
-Best one of the three gets the #2 spot behind Howard
-The other 2 go to GR
-Fulcher goes to Toledo
-If one of the fringe goalies gets lost on waivers, try to leverage one of the surplus fringe dmen in GR (Russo/Lashoff/McIlrath) to a team in exchange for a fringe goalie
-Explore trading Howard at the deadline. If he can't be moved but plays well enough, offer him an extension in the $3-4M range for 1/2 years that offers the flexibility to bring in a decent #1B or an upgrade if needed in those 1/2 years.