Cheddar cheese is not vegetarian.
Cheddar Cheese is real cheese made from cows milk so it's not vegetarian.
Cheddar Cheese is a real cheese and is natural as well.
But Cheddar Cheese sometimes has the addition of other ingredients mixed into the cheese to help give the cheddar cheese it's flavor.
When cheddar cheese is made it already has a cheddar cheese flavor to it although when the cheddar cheese is young it has a milder flavor.
As the cheddar cheese ages the flavor get strong and stronger so the older the cheddar cheese the stronger the flavor.
Also some cheddar cheese gets additional flavor by addition of other ingredients such as the addition of chilis, onions or cracked black pepper.
Also as for the orange hue that is seen in some Cheddar cheeses derives from the addition of ground annatto seeds.
As cheddar cheese ages the cheddar cheese loses it's moisture content and then dries out which adds to the stronger of the flavor.
Cheddar cheese is allowed to age awhile before it is sold so that it gets the cheddar cheese flavor.