Well thanks. Is there anything else? I heard that the Operative, when combined with a small body size, can jump higher and move faster than every other character. Other than Operatives of the same caliber.
That's correct, but it counts for every class.
Basically, you have classes (Soldier, Medic, Operative, Engineer) and you have bodytype (Light, Medium, Heavy)
While you create a character, you have to chose a bodytype. This cannot be changed during a match.
Bodytypes affect: Movement speed, Freedom of movement. Amount of Ability pips (Represents how many times you can use your abilities in rapid sequence), Amounth of health, Primary weapons, Secondary weapons, Hitboxes.
The Lighter you go, the more movement speed and freedom you have and the smaller your hitbox is. You will have less health, less choice of weapons,... I think you get the point. It's all covered in that link as well.
Classes can be switched during a match (It's very easy and important). You need the different classes to do different objectives.
Any class can be combined with any bodytype.