About types of Lab - in the UK, there are two 'types'. Working and show. In the USA, they tend to call them English and American types.
Working types of lab have been bred to refine their working abilities. They tend to be leggier, leaner, finer and smaller of head. The characteristics a working lab is bred to refine are those used for their traditional work - retrieving game, so speed, style, brains, nose and bidability.
Show types are bred to refine whichever 'look' is in fashion at the time, currently quite stout with a big, broad head and chest.
A good breeder of either type will also aim to ensure a good all around dog with a true Labrador.
Colour has little impact on the character of the dog, nor of it's intelligence or attitude. Chocolates did suffer when they became very fashionable and some people were breeding just for colour and money, with no thought for the final character of the dog. Black is the dominant/original Lab colour.