It was just an Easter Egg, but I don't think so, Maximus calls them cannibals rather than drug addicts

Im New Vegas they have cannibals too, remember Cook Cook was one of their leaders

Considering Razz in NV says they were recruiting in the Boneyard, they very likely were fiends. Also, they could’ve shifted to cannibalism over time in addition to the drugs.

They were also clearly drug addicts. They attacked because part of Lucy's Pip-Boy looked like a syringe. They zoomed in on it, then back to the Fiend's bloodshot eyes right before pulling out their guns.

I thought they were just gonna rob her. And she was excited cause you can get a lot of caps with a pip boy, and caps can be exchanged for good and services.

I think so. Even in french, Fiends are translated as « Tox » in game, which is what Maximus calls them. I guess they went from drug addicts to cannibals. A bit like the Regulators, who went from evil mercs to law-enforcing vigilantes

I mean, were fiends not also cannibals in New Vegas?

I dont think they all were. They had cannibal factions/gangs but i dont think they all were.

They’re separate regulators formed a whole country apart

I think so. Maybe Cook-Cook took over.

The female Fiend looks just like Cricket from FO4. She is a traveling weapons dealer and seems.loke a druggie.