Not going to address everything but on a different site someone posted that last year the Vikings ran more traditional 3-4 packages and then dropping Pace and bringing in Metallus against the pass as the base defense. But this year, they've done a bit more 4-3 and Redmond is a good "3 technique" guy but Hargrave isn't playing well enough to demand double teams and that puts the linebackers a bit out of position to watch the cut-back lanes. Essentially, the injuries to Cashman and Van Ginkel and Pace playing worse has really hurt the linebacking corp (and they thought Turner was fine). To get better the vets (Allen and Hargrave) have to start playing better. Both have been MIA this season.
Secondly, I don't think Addison has 1st/2nd round trade value.
Lastly, Jackson didn't have a great game but (and I may have missed something) he isn't being physically outmatched. He's learning the difference between NFL caliber and college caliber pass rushing. So I'm not quite as worried about him, so long as he can stay healthy. But a new o-line coach might be an off-season priority.