I found this GitHub repository that contains collection of several different intelligence agency domain seizure pages, including FBI domain seizure.
It is meant to be used by said agencies for real seized domains, but I figured out one of my April Fools jokes on my own websites would be to include the FBI domain seizure page for just one day and display it to anyone who visits the page on April 1st for the first time.
The domain is on a national TLD outside U.S. so it's fairly obvious that FBI couldn't seize that domain (and it's a 3rd level domain, too).
However I would still make sure that I won't face any kind of jail for that if I misuse the domain seizure template for a silly April Fools joke. I would add a button to it that will be labeled as something like "Details on this seizure" or something, and clicking it will display an alert box saying "APRIL FOOLS" and redirecting back to the real website homepage.
I also figured out that just for the sake of being sure, the page would visibly include a disclaimer stating that that page isn't real and was only installed for the purpose of a one time April Fools joke and does not intend to misinterprets it as a real domain seizure, and that the artwork is licensed under Public Domain as an official U.S. government agency artwork.
Am I still in trouble if I go with that route? Is it too overboard?