I dunno if this is the right section, but... do the food vendors on the concourse (not the convention center fare but like the boba place, psycho donuts, the ramen stand, last year's tai-yaki) and even the flying hands massage guy... do they rent that space via Fanime/ARG, or the con center itself? Just curious.
Dunno the answer to your specific question - I believe it's through the convention center, though - but it won't matter as far as the chibi taiyaki is concerned. Sweet Breams closed rather suddenly and unexpectedly earlier this year. A real shame, too, as they were very unique in a downtown full of restaurants and markets, Japanese or otherwise. There are only a handful of dedicated dessert/snack places here in San Mateo, and I really enjoyed their versions of taiyaki.
Wonder what the owner is up to, if she's continuing on somewhere else or if she's moved on to other ventures.
These vendors work directly with the San Jose Convention Center and we (FanimeCon) work with them on who to get. If you have questions, feel free to PM me and I'll try my best to answer.