Agreed, most of these shows will be light on comics. But 3-4 of them will be at least somewhat comic focused, which is a lot to have in a 4-6 week span at this time of year. If this Halloween show is going to be comic focused then it comes into a fairly saturated market.
If this Halloween show is mostly horror themed (and they've said on FB that this show is replacing their Terror Expo) then it will compete against other such shows, one of which is in the same market.
If they take that October 27-29 time slot, which I think is likely based on the Halloween theme and dates they previously announced as tentative for their main show, it may be tough for them to find an audience. The San Antonio crowd may be divided, or at the least have wallet fatigue from the other shows, and they'll be less likely to draw from surrounding cities. I'm scratching my head.