I stopped wondering years ago about who is enlightened because I think it is always motivated by tanha. What we can know about a teacher - beyond speculation- is whether they point to the present moment in a way that helps us to begin to insight such moments. The rest is wishful thinking.
The Anguttara nikaya commentary tells the story of one teacher, after the Buddha’s time, who had many pupils all of whom attained arahatship.
. But he was still a wordling - not even a sotapanna. However, he understood the tipitaka very, very well; knew the letter and the meaning and so was a great teacher.
see (Angutara nikaya Ekakanipata pali (the book of the ones) Nivaranapphahana-vagga (abandoning of hindrances) 6th sutta; about the Thera Gamantapabbharavasi mahasivatthera ). Many of his students became arahant[not entirely sure of this number I can`t find the orginal pali at the moment]
Later he himself attained.
here is a link to an account:
Mahashiva, Mahāśiva, Maha-shiva, Mahāsīva: 7 definitions (wisdomlib.org)
and
http://www.vipassana.info/maha/mahasiva.htm
Scroll down and you will see his name.
Mahasiva Thera. Resident of Vamantapabbhara. He was among the last of the arahants, and had taken part in various assemblies led by the Bodhisatta (J.iv.490; vi. 30). It is probably this Thera who is referred to as Gamantapabbharavasi Mahasiva in the Anguttara Commentary (AA.i.24, 29). He lived in Tissamaharama at Mahagama, and was the teacher of eighteen groups of monks. One of his pupils became an arahant, and, being aware that his teacher was yet a puthujjana, went to him and asked his leave to be taught a stanza. But Mahasiva said his pupils were so numerous that he had no time to give him a stanza. The pupil waited for a whole day and night, and then getting no chance of learning, said, If you are so busy now how will you find time to die? Mahasiva heard and understood, and exerted himself strenuously for thirty long years, at the end of which time he became an arahant.
The commentaries explain that examples like this where a puthujjana teacher helps his students to become ariya is like the Buddha was their teacher (because the putthujana teacher is using the Buddha’s words).