Williams would definitely have benefited hitting in the stadium. Not sure about Joe in Fenway, though he’d have loved playing with Dom. Depends on if he lofted balls or hit line drives for homers primarily. A line drive hitter (Jim Rice, Manny) is hurt by the wall. Home runs turn into singles. If Joe was a lofter (Dwight Evans, Rico Petrocelli), he’d have benefited.
Joey-D could have easily reached 600 or more if he played for any other team in any other ballpark other than Yankee Stadium. If in Fenway, his shots would have at least bounced off the top of the Green Monster and fell for a double or triple, or even perhaps an inside-the-park HR .. yes, Joe D was *that* quick on his feet ...
Consequently, Teddy (frozen head) Williams would have had a field day shooting at "Ruth's Porch" in Yankee Stadium ... all that remains is counting how many dingers would have ended up in the Bleacher Creature section :)