There is a lot more to dreams than some people can even realise.
To pass information in a dream, you must understand a basic concept.

If I contact you in a dream, and show you an ACTION MAN doll. To me it is just a doll which brings back memories of childhood.
The information received by you, may not even resemble a doll.
If you have a relative that died in a war, you may see death and misery.
You may see your favourite toy from childhood.
Association is the key to what is experienced in a dream state.
The information can only go from one person with full control over their dreams and emotions to another of same training.
First think of all the problems that can, and do occur, then think of a way to bypass them.
With 1000s members on here I am sure an effective experiment can be conceived.