Mix 1 1/2 cup white sugar, cinnamon, and pecans together in a bowl; set aside to be used as filling later.
Whisk yeast and warm water together in a separate bowl; sprinkle with 1 teaspoon white sugar. Continue whisking until well incorporated. Set aside until yeast softens and begins to form a creamy foam, 10 to 20 minutes.
Place warm milk, 2/3 cup white sugar, 2/3 cup melted butter, salt, eggs, and yeast mixture in a stand mixer; mix until all ingredients are incorporated.
Add 4 cups flour; mix on medium until completely smooth, about 5 minutes.
Transfer dough to a large bowl; knead the remaining 4 cups flour into dough with hands until dough is slightly stiff and sticky, 10 minutes.
Transfer dough to a large greased bowl; cover bowl with plastic wrap.
Let dough rise in a warm place until doubled in size, about 1 1/2 hours.
Remove plastic wrap from bowl and punch down dough. Set dough aside to rest for 5 minutes.
Roll dough out onto a well-floured surface, forming a 15x20-inch rectangle.
Brush entire rectangle of dough with 1/2 cup melted butter; sprinkle with cinnamon-sugar filling. Tightly roll up dough, starting from a long end and pinch edges together to seal.
Cut dough, using dental floss, into 15 to 20 slices.
Grease a 9x13-inch casserole dish with 1/2 cup melted butter; sprinkle with 1/3 cup white sugar.
Arrange cinnamon rolls close together in the prepared casserole dish. Allow to rise in a warm place for 45 minutes.
Preheat oven to 350 degrees F (175 degrees C).
Bake rolls in the preheated oven until golden brown, 25 to 30 minutes.
Beat confectioners' sugar, 2/3 cup melted butter, vanilla extract, and maple extract together in a bowl until smooth.
