Your magic number to clinch the postseason is off by 1 because the Brewers own the tiebreaker over the Reds. Reds have 65 losses so the most wins they can get is 97. Brewers have 83 wins which would make the magic number 14 not 15.
Also for the same reason your magic number for the Pirates to be eliminated is off by 1 as well. Brewers have the tiebreaker over the Pirates and Pirates have 75 losses. Most wins they can get is 87 which means the magic number to eliminate them is 4.