Your question makes it seem like you are an attorney asking. Ill assume that unless you tell me otherwise.
The alternative to the actual statements would be an affidavit, or sworn statemt, as you suggest.
The testimony or an affidavit from your boss would also be good, and from anyone else who knew of your bosses intent to use the mark.
If you are not a trademark attorney and you are trying to defend the itu in a cancellation proceeding, I would highly recommend working with a trademark attorney to ensure that the best options are examined, and so that nothing is missed.
I am not your lawyer and this comment does not create an attorney-client relationship. Plus, it is not a good idea to base legal decisions solely on comments posted to an open forum board. However, I hope that you will seek the advice of an attorney if you feel that your situation requires such expertise.
Agreed, an affidavit is one way around this, but be cautious in your wording of the affidavits because depending on the wording, if swearing the discussed the intent in a recorded chat log could open up the possibility of the logs themselves being requested by opposing counsel.
My disclaimer is simply that Avvo already has an adequate disclaimer.
An affidavit is ok, but it's not quite the same as an affidavit backed up by documentary evidence. Is there other documentary evidence that you could use? Are there internal company emails discussing plans to use the trademark? Is there a business plan? If all you've got are the vendor emails, I would be inclined to redact out the obscenities -- they're completely irrelevant -- and submit redacted copies. Good luck.
I agree with Attorney Lewis -- the supporting documents that purport to establish your company's bona fide intent to use the mark must be produced. Those documents will be responsive to the other side's Request for Production of Documents. Which means that you MUST produce them or else face a sanction -- which could be a negative inference that you have no such supporting documents. At which point the declarations from your subcontractors become suspect, lose evidentiary weight and could be deemed inadmissible.
The default TTAB Protective Order [availble via the link below] automatically applies in all cases unless the parties craft their own version and get it approved by the TTAB. The default Protective Order has a "Highly Confidential" designation that shields documents so designated from public disclosure. You and your own trademark attorney need to decide how best, if at all, to shield the subcontractor's emails from disclosure [not at all, redaction, or protection order]. I would strongly suggest not at all. By virtue of being your subcontractors they need something from you: work and money. In exchange they can withstand some very remote possibility of embarassment over their spicy language.
You need a trademark attorney. Good luck.
The above is general information ONLY and is not legal advice, does not form an attorney-client relationship, and should NOT be relied upon to take or refrain from taking any action. I am not your attorney. You should seek the advice of competent counsel before taking any action related to your inquiry.