Hawaii will never allow feds to usurp local authority. In fact, Hawaii is one of a few states that does not afford peace officer status to federal law enforcement. This is why feds can never pull you over for traffic stops on state and city roads. Some feds donhave ticketing power on fed lands like Haleakala, the airport, and some parks, as well as military property. This forces feds tonwork with local agencies instead of doing traffic stops unrelated to a federal crime. Hawaii wants more local police policing and trust me HPD will be ordered to dirty everyone up if CCW is ever granted.
Sheriffs, DLNR, and AG Agents have state wide police power they do not need peace officer status. Local PDs can generally go to outter islands armed if on official duty and cleared by island Chief or to assist. This used to be whenntheybattended meetings or did recruitment trips, but most recently you seen this with HPD on Mauna Kea. The local prosecutors offices also general have the ability to deputize federal law enforcement officers to work with prosecution investigators. This is not too common. Other than that, Feds are not afforded peace officer status in Hawaii (couple kooky provisions allow CBP very limited peace officer status under very specific circumstances) Feds can carry pretty much anywhere except state and fed courts. Fed agencies generally have agents register their personal weapons (usually pistols) as agency weapons so even personal weapons are considered service weapons when shtf and they smoke someone. Feds have no peace officer authority to enforce HRS, but generally can intervene if they observe a felony. But they cant be blue lighting people up for speeding and stuff like in the mainland. Probably pull up 20 articles on peace officer status in Hawaii if you search.
I'm still trying to understand exactly what you're trying to say. Your two posts some across as somewhat different.
-Federal police do not "usurp" local authority in a great majority of cases anywhere, not just in Hawaii. For the most part, federal police enforce federal laws, not local laws.
-Federal police do not count as "law enforcement officers" if they are not in Hawaii on official business according to state law. I know the term "peace officer" is used elsewhere, but I'm not sure it's used in Hawaii, at least not anymore. Can you explain this term and how you intend to apply it?
-Federal police absolutely have arrest powers in Hawaii, but as mentioned before, they only enforce federal law. Federal police can certainly enact an arrest by "lighting you up" if they have the legal compulsion to do so.
It sounds to me like you're saying Hawaii has something against Federal Police, but I just don't think that's the case.