A brand kit, used strictly, is the agent's own identity package. Logo, color palette, the typefaces they're licensed to use, and a set of templates so their flyers, social posts and email all look like they came from the same business. It's a one-time build, it belongs to the agent's practice, and it goes on the next listing and the one after that. On that reading it isn't a cost of selling your parcels and it shouldn't be on your invoice.
The loose usage is where the confusion comes from. Some vendors sell a per-property look, a name for the property, a logo mark for a subdivision or a ranch, and call that a brand kit too. That one genuinely is tied to your listing. So ask which of the two the $1,200 is. One question settles it.
On who pays generally: it varies by agent and by what the listing agreement says, and the listing agreement is where it should be written down rather than in a menu emailed separately. If you're being asked to reimburse anything, get the list and the amounts in the agreement itself.
For land specifically, the pieces that move buyers are usually plat and survey graphics, access and easement notes, and any soil or water data you already hold. Those are cheap to produce compared with video. Aerial photography is priced separately almost everywhere and the pilot needs to be certified to fly commercially, so ask whether that's included or an add-on before you assume it's in a package.