Ela tinge

O romance canônico Leia, Princesa de Alderaan mostra as escolhas freqüentes de guarda-roupa e excêntrico de Holdo adolescente:

Amilyn Holdo wafted along, the same slightly glazed expression on her face. Her hair had been dyed pale blue with orange tips.

'Apparently Holdo goes her own way'....which was a good reminder that it shouldn't matter to Leia what this girl wore or what colors she dyed parts of herself, or that she always spoke in the same airy monotone.

- Chapter 6

Holdo's hair had been dyed the same green as her cloak, though at least only the cloak had little bells sewn all over it.

-Chapter 8

Holdo, whose hair had been dyed glittery blue...

- Chapter 32

A wiki que você cita em sua pergunta tem a seguinte citação.

Holdo became disinterested with the peaceful culture of her homeworld, so she expressed herself by dyeing her hair vibrant colors, wearing vibrantly-colored clothing, and going on daring escapades.
_{Amilyn Holdo}

Também afirma que ela é uma fêmea humana de Gatalenta, então parece que ela é humana completa.

O Dicionário Visual do filme oferece informações sobre a rotina de coloração do seu cabelo, além de confirmar o motivo > por que ela tinge o cabelo rosa.

Em suma, sim, ela é humana. Ela tinge o cabelo usando algo chamado chromomites e suas freqüentes mudanças na cor do cabelo refletem sua herança, vindo de um planeta boêmio famoso por seus poetas e artistas.

A STRIKING APPEARANCE

Holdo doesn't wear the combat khakis and camouflage kit most often spotted in Resistance bases. Instead, her dyed hair and eye-catching clothing show her fierce devotion to her homeworld of Gatalenta and its independent spirit. Gatalenta is known across the galaxy for its poetry and the tranquility and compassion of its inhabitants,

Sim. Seu cabelo está tingido.

Amilyn Holdo pinta o cabelo de várias cores de acordo com seu quadro na Wookieepedia .

De acordo com um artigo nerdista :

Anyway, Holdo was different from others on her world: she wanted to express herself more and did so by regularly dyeing her hair in various bright hues, wearing bold-colored clothing, decorating her gear with glitter, and generally setting herself apart. She was quirky and often spoke in riddles. Leia called it Holdo-speak.

Tanto quanto sabemos, ela é uma humana do planeta Gatalenta. Quanto à tecnologia de cabelo morrendo, nenhuma foi revelada ou mencionada até o momento.

O vice-almirante Holdo usa chromomites para tingir o cabelo dela. Ele diz isso no Dicionário Visual dos Últimos Jedi na página 40.