Okay, you had a pre-lucid dream (so it sounds like you had a vague idea that you might be dreaming) and called two of your friends.
And you wonder, “How valid is the information they gave me in the conversations?”
If this was my experience, I would call the two people, and tell them the dream conversation, and their reply. Then I would ask them, ‘Does that sound correct, literally or symbolically?’ (since we see in dreams and lucid dreams that sometimes dream figures respond with either literal, symbolic or nonsensical responses).
Here it becomes more complex, since people are people. For example, I recall asking a friend if she had gotten a new silver convertible car? She told me, ‘No.’ But later I learned that her husband had purchased a new silver convertible (as I had dreamt) — and she had answered literally by saying she had not (though her husband had).
Then you have the issue of ‘memory’ and subconscious association — as in, ‘Had you somehow heard about the information, then forgotten it, and now dreamt it?’ Or, had you heard some things about these people, then subconsciously associated it together, and dreamt the result of those associations (e.g., a woman mentioning her body temperature in waking life, and then you later dreaming, ‘She’s pregnant!’).
And of course, you have some dream encounters where you get symbolic information, but the waking person, when questioned, does not see the symbolic aspect. And you have situations where the information seems your projections or simply nonsense.
As you can see, it’s complicated!