Sorry Squishy Gooigi and Glow-in-the-Dark King Boo.
Nintendo Treehouse Representative Nate Bihldorff has confirmed that Luigi's Mansion 3 will not support any Amiibo in an interview with the YouTube Channel GameXplain. Also, Bihldorff had nothing to announce about DLC, whether the game would have Labo VR support, and even who the composer for Luigi's Mansion 3 is. Luigi's Mansion 3 is planned to release later this Fall.
You can see their full interview, here: