After talking with people and thinking it over some more, I contacted Lord B. and brought up the potential legal issues of me making cookies for tea room.  I didn't want to leave him hanging, so I offered to procure store-bought (or bakery-baked) tea treats on his behalf, if needed.  It isn't needed; they have things well in hand. 

So, cookie-wise, no volunteering for me at the con.  Which is fine.  I did learn a bunch while baking - for example, how very long it's been since I've done serious baking.  I was able to make one final batch of vegan + GF cookies, using only ingredients that could be acquired in Victorian England without much travel - just to prove to myself that it could be done.  They do still get chewy after a couple of days - although less so than the last batch. 

So now, back to frenzied con prep, interspersed with frenzied pre-winter yardwork, the heavy-duty project stuff at work, and the usual day-to-day.