Of course Dr. Burstyn's perspective would be most welcome. He should be within driving distance from FDA HQ.
However, I'd be weary of financial contributions from vapers or pro-vaping organizations to any speakers, because they may be used to paint them in a negative light as a perceived COI.
Financial Contributions to cover things like Transportation, Hotel/Food, Rental Cars are quid pro quo for attracting a Speaker for an event like this FDA Workshop.
And would Not Raise an Eyebrow with anyone on a Speaking Circuit.