Holy fuck this took half a fucking day.
I did a proof of concept and it works pretty much exactly like you think it would, minus the fact that the links to the threads themselves are busted because the board uri in the links is /site/ (the catalog I overrode) rather than each thread's respective boards. There are probably ways to get around this, but the easiet I suspect would be if the uri was included in each object(?) of the json file.
Just to be clear, I did NOT write a script. I merely proved that a competent javascript programmer could probably VERY EASILY write a script. This does not mean I will not try, but I make no promises; I literally started learning js this morning. To briefly document what I did, all I did was download the json data from the catalogs, which can be done by either replacing .html with .json and saving the page or with a function call to api.localRequest . The .json files are very simple to concatenate: just remove the closing bracket in the first file and the opening bracket of the second file and just combine them with json0 + ',' + json1. Then in the call to api.localRequest that the catalog makes on refresh, I swapped the argument with a link to the .json file uploaded to 8chan.
Please, for the love of Christ, tell me someone else is interested in helping me on this fucking thing.