A: Technically yes, but it is very risky. Nintendo bans consoles that connect to their servers with tampered titles or missing DLC entitlements. Use 90DNS or Incognito to block Nintendo servers before going online. Do not launch the game with Wi-Fi on if you care about your console's online status.
If you find a "Super" bundle NSP that includes the base game + update + DLC in one file, install that via Tinfoil's "Install from Unsorted" folder. This is the most foolproof method. one piece pirate warriors 4 nsp update dlc work
Check the bottom corner of the title screen. It should show the latest version number (e.g., v1.0.13). A: Technically yes, but it is very risky
When the versions align, the feature set works flawlessly: Do not launch the game with Wi-Fi on
You can usually drag and drop the Update NSP and all DLC NSPs into your installer at once.