Luffy is in slight shock after seeing someone physically hurt in season 1 episode 6. Other moments within the show, different characters experience moments of anxiety, but no anxiety attacks I believe (season 1)
In the second episode when buggy first demonstrates his devil fruit he detaches his head (for fun and games really) and it lands on a lady's lap and she screams.
In the end of the seventh episode nami screams the name "arlong" in rage (this scene may be distressing for those with a self-harm trigger too) Many flashback scenes in the 7th and 8th episode have screaming and crying in it, I had to have some of it on mute (as a person with misophonia) and the rest on low volume.
Luffy screams out of excitement occasionally too.
If you hear Garp start laughing in weird tense moments, (usually after a conversation) he screams and yells straight after.
Throughout the season there is a "fishman" character who looks like a sawshark, with the iconic nose and a fin on his back. His skin also resembles a shark's, but otherwise he is humanoid.
A character's teeth are damaged and they all suddenly fall out, blood everywhere. A new set of teeth instantly pushes back through the gums. This is all an extreme close up
While it does not show the head being squashed, Alvida does rear up her mace during an interrogation and with her body and the swinging motion being the thing the camera focuses on, the sound of something being struck is heard, followed by a quick pool of blood that a cabin boy has to clean soon after. Roughly 7 mins into the episode.
I'd argue no. One child chooses to indenture themself for their own reasons. There are also kids held captive with their parents earlier in the show. Aside form these two vague instances, I don't think there's anything else in season one
Unfortunately, the whole setting is based on a giant ocean world with islands being the only source of land that people live on. Sea travel in boats and unnatural flotation devices (such as barrels) and shots of ocean happen on a constant basis.
A character on the verge of starvation says he'll kill himself to avoid starving to death. This character is rescued and never attempts to hurt himself.
(Season 1) Koby often listens to Garp’s private conversations without him knowing. Garp later finds out and quickly dissaproves of this, and Koby does it again afterwards.
Not debated, but touched on. There is commentary about fulfilling ones dreams versus dying trying and the sense in it. There are conversations about death, living a meaningful life, etc. This comes up most significantly in EP5.