Cook onion and garlic in butter in a medium skillet over medium-high heat, stirring constantly, until tender. Add wine. Bring to a boil; reduce heat, and simmer, uncovered, until liquid has evaporated.Set aside.
Position knife blade in food processor bowl; add shredded Cheddar cheese and 2 packages (11 ounces) cream cheese. Process until cheeses form a ball, stopping once to scrape down sides. Remove mixture to a medium bowl. Stir in onion mixture and pimiento. Cover and chill at least 30 minutes.
Shape mixture into 3/4" balls. Place cheese balls on a wax paper-lined jellyroll pan. Cover and chill at least 8 hours.
Roll half of chilled balls in parsley and half in pecans. Cover and chill until firm.
Wrap plastic wrap around Styrofoam cone, sealing completely. Spread softened tub cream cheese over plastic wrap-coated cone, covering cone completely and making a 1/2"-thick layer. Sprinkle coated cone with chopped parsley.
Press a circular row of crackers into the cream cheese-coated cone at the base. Attach a circular row of cheese balls at base of cone just above cracker layer, using wooden picks. Attach a circular row of olives above row of cheese balls, using wooden picks. Gently press another row of crackers into the cream cheese-coated cone, creating a shingled effect. Repeat procedure, working in circular rows and covering cone completely.
Cut a large star shape out of each pepper half, using a sharp knife. Secure with a wooden pick at top of tree. Serve remaining cheese balls on crackers around base of tree.
Note: For bite-size whole wheat snack crackers, we used Wheat Thins.