Make sure you're loading it from the sysNAND and not just booting up the system. To do so, you'll need to enter rxTools manually by holding the L button down while rxTools is booting, select boot and then boot into sysNAND through there.
Additionally, you'll still need to use Free Multi Patcher so boot that up once you're in sysNAND, have all patches on and use the save and quit function. Put it on automatic even if you want so it's just as simple as opening it once. After that you should be able to use eShop and Miiverse but only as long as the console stays on, and when you wish to turn it off an back on just repeat these steps.
While this is true, it's not exactly hard to find the latest one on the website here. If needed one can just trace back from the latest firmware of their system until they find the last instance of the app being updated, but in this case I already put which firmwares updated the app beside it, and 3Dbrew can be a bit confusing as the Title ID isn't full, only showing half of it above the list of the apps and the rest on the bottom, meaning you have to copy/paste them together to get the full Title ID. But whatever anyone finds more convenient.
As for 3DNUS, that was also linked in this thread in the last page.