Contributions to the TFSA mimic those for RRSPs, so putting the warrants into the TFSA has precident. Not sure how the warrants add fuel to the brokerage shorts, if they haven't been exercized. Perhaps I'm missing something?

What are they valued at when first put in?

Excellent question, the answer from my broker was that the warrants would use up $0 of contribution room - which is the same as the premium paid for the warrants in the issuance. I'm not 100% sure how the exercise process works as the fair market value for anyone participating will likely far exceed the $5k contribution limit. I'll enquire and let you know what I find out.