I made a soft sculpture last year of the Mighty FSM, so I will share a simplified version of construction that you could use to make your costume.
For the noodles: I cut rectangles of fabric 7 inches by 10 feet of noodly looking fabric. After sewing the sides of the noodles together, sew one end closed as well, turn right-side-out. Put thin wire the length of the noodle inside, and you can add stuffing if you want. It's very time consuming, but if you use a thick dowel or stick to push the stuffing through it goes faster. Hand sew the other side shut.
Meatballs: I made dozens of tiny meat-colored balls and sewed the balls together to make two big meatballs. This took forever, so I would recommend making just two big meatballs. There is fuzzy fabric you could use for texture. To make a ball, you cut out five football shaped pieces of fabric and sew them all together.
Eyeballs: Make two stuffed balls like the meat balls, and make sure you have pupils. Hand sew the eyeballs to the ends of some noodles, and make sure the wire is enough to support the eye balls.
If you want to be really fancy, make your shirt and pants out of the same fabric as the noodles. Just use a pajama pants pattern for the pants, and think of a sweatshirt for the top.
You'll need a friend to help attach the noodles to the shirt. (You'll probably want to be wearing the costume as the noodles and meatballs get placed.)