The answer regarding whether this was okay depends upon the nature of the other "supporting documentation.
If the additional supporting documents make the allegations of the complaint vague and uncertain, the defendant will most likely file a special demurrer.
If the supporting documents conflict with the rental agreement, you might have a serious problem in alleging a viable cause of action.
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, consult with your own attorney.