[color=red]1) The balls in this box are blue, orange and red.
[color=blue]2) The balls in this box are either blue, orange or red.
[color=indigo]3) The balls in this box are blue, orange or red.
[color=red]4) All the balls in this box are blue, orange and red.
[color=blue]5) All the balls in this box are either blue, orange or red.
[color=indigo]6) All The balls in this box are blue, orange or red.
Which of the above can one use if some of the balls are blue, some are orange, and some are red.
The balls in this box are blue, orange and red. (It may also be interpreted as each ball having the three colours indicated)
The balls in this box are either blue, orange or red. (When you use ‘either’, the structure is ‘either blue or orange or red’. It may mean that the balls can be of one of the three colours)
The balls in this box are blue, orange or red. (As in 2 and the balls can be in one of the three colours)
The addition of ‘All’ does not matter anything much to the meaning except emphasis.
All the balls in this box are blue, orange and red.
All the balls in this box are either blue, orange or red.
All The balls in this box are blue, orange or red.
Which of the above can one use if some of the balls are blue, some are orange, and some are red? (You need, probably, to be more specific to avoid ambiguity as shown below, for the word assortment or mix makes your meaning clear, I think.)
The balls in the box are an assortment of blue or orange or red ones.
The box contains a mix of blue, orange and red-coloured balls.
Nevertheless, we need to look out for other comments.