While in Hawaii, Mishima gets sick from drinking the tap water, which Ryuji points out is unsafe to do in foreign countries, however this mostly only applies to third world countries and other countries with a contaminated water source. Hawaii tap water, specifically Waikiki where the protagonists are, does indeed have safe to drink tap water.
When the Phantom Thieves send a calling card to Shido by hijacking the television broadcast, the broadcast shows the thieves in their gear talking to the camera. Since video recording doesn't work in the Metaverse and the costumes only exist in the Metaverse, there would be no way to get a shot of the team in costume.
Incorrectly regarded as a goof: The Phantom Theives in game acknowledge this by stating that if Sae Nijima thought there would be cameras in her subconscious world, they would be able to use them in the shadow world.
Incorrectly regarded as a goof: The Phantom Theives in game acknowledge this by stating that if Sae Nijima thought there would be cameras in her subconscious world, they would be able to use them in the shadow world.
The protagonist has a criminal record and is currently on probation. Rather than risk violating his probation, and getting into a physical confrontation with Eiko and Tsukasa, they should have just gone into Mementos and changed Tsukasa's heart.