North Euboea clearly had an Arvanite component earlier on:
Lisada - Northwestern Euboea:
Nikola Kostapetr, Aritidi Kostapetr, Manol Simos, Nikola Kara binar, Kiryako Karabinar, Cyano Karabinar, Yani Apostolo, Dimitri Kamarya, Nikola Kamarya, Nikola diger Kamarya, Mihal Karasuni, Manol Mavro, Yani Balusi, Yani Zinota, Yorgi Iskinari,* Nikola Vasilyor, Kosta Salusi, Kozma Salusi, Yorgi Salusi,
tetim me-i karye-i L i s a d a
Yorgi Salusi diger, Nikola Salusi diger, Yorgi Vasila, Yorgi Ivreto, Yani Ivreto, Kiryako Ivreto, Dimitri Ivreto, Nikola Ivreto, Luka Sayita, Yani Luka, Nikola Luka, Nikola Salvit, Manol Vasilikör, Kosta Vasilikor, Yorgi Makri, Istamad Makri, Nikola Makri, Yani Vlahoni, Yorgi Vasilinor, Istam ad Vasilinor, Kosta Agapito, Nikola Kamaki, Dimitri Kamaki, Yani Kamaki, Petro Kamaki, Dimitri Romaniti, Hristofor Romaniti, Aleksi Romaniti, Dimitri Arab,* Nikola Kamarana, Mihal Kamarana, Yorgi Rasula, Nikola Rasula, Dimitri Rasula,
Gin damad-i Rasula, Nikola Krasos, Kostandin Krasos,
Nikola Guri,
Petro Guri, Istefan Palusi,
Yani Kursari, Dimitri Kursari, Vasili Sarandi, Mihal Sarandi, Yorgi Kavaco, Dimitri Kacavo, Petro Kavaco, Todor Atlazi, Dimitri Atlazi, Aleksi Istasuli, Nikola Arcuras, p.* 147 Yorgi Istasuli, Istamad Lazomondas, Andriya Midali, Yorgi Kisaki, Nikola Kisaki,
Dimitri Toto,
Nikola Toti, Yani Sarandi, Yorgi Toto, Yorgi Morya, Yakomo Morya, Dimitri Morayit, Nikola Lalandari, Todor Lalandari, Istefan Lalandari, Yorgi Lalandari, Mihal Kukyopulo, Istamad Harikopulo. Yorgi Livada, Dimitri Livada, Yani Livada, Mihal Halkya, Yorgi Tramasi, Istamad Tumaniti, Yani Avloniti, Gini Agriyomat, Mihal Agriyomat, Yani Agriyimat, Yorgi Agriyomat, Petro Anastas, Hristodulo Kamaki, Manol Davikar, Nikola Kataduka, Istamad Ivreto, Apostoli Drako, Paraski Tomadya,
Gini Landari, Kiryako Landari, Mihal Varas, Garuso Davas, Yani Mistros, Nikola Palyatura, Yani Palyatura, Dimitri Valkyoti, Dimitri Anastas,
Dimitri Kursari, Yorgi Avlonit, Trogyos Kadikyopulo, Yani Harikyopulo, Andriya Balayot, Istamad Kalayot, Vlasi Gromyo, p.* 148 Petro Romana, Yani Crigar, Petro Balas, Manol Agramyot, Yorgi Agramyot, Nikola Saluti, Yani Karalasa, Papadimitri Kisaryo, Kosta Iksano, Istamad Maromat, Yorgi Nyaka, Todo Dugar, Manol Vavasi, Petro Akaras, Saro Dragumano, Katokuki Cikna, Muruzi Ihsalya, Kosta Mavasari, Potino Muvasa Iksida, Nikola Anastas, Yani Vatikyot, bîve Arhondo, bîve Sumalya, bîve Malalya, bîve tu Vasila, bîve tu Yakomo, bîve tu Simiyu, bîve Harulya.
https://satellites.pro/Lichada_map
I have severall other villages. And not all Arvanites carried Albanian names, some of them had Greek names too. I agree that Arvanites were self assimilated by their wish. I don't know about their actual percentage in the north but considering Arvanites in the south were not hellenized it is easy to see that their percentage was not the same in the south as in the north.