FOR BISCUITS: Sift dry ingredients and whisk together. Divide margarine into pieces and incorporate into flour by hand or with a pastry cutter. Margarine should be completely mixed in (aka no chunks!) Add soy milk and mix by hand. Dough will be fairly wet. Refrigerate dough for at least 1 hour.
On a clean, dry, floured table, flatten dough by hand and sprinkle flour over the top. Bake biscuits at 400 degrees for 25 minutes; test for doneness by piercing center of one biscuit with a toothpick. If the toothpick does not come out clean, bake for 5 minutes and recheck.
FOR GRAVY: Sauté sausage in large sauté pan for approximately 5 minutes (until seared), then set aside.
Meanwhile, heat oil over medium-high heat; add garlic and seasoning mix. Whisk until garlic starts to brown—do not burn. Add flour and whisk thoroughly to form roux.
Whisk in soy milk, then cook over low-medium heat until gravy thickens, stirring frequently to prevent burning and sticking. Combine gravy and sausage and stir thoroughly until evenly distributed.