Yes, Hakham Meir.
Meir Yosef Rekhavi (born 1962) is a British born Karaite Hakham and author.
Born in Leeds, England, Rekhavi came from an Orthodox Jewish family which had migrated to northern England from Tukums, Latvia via Germany in the early 1900s. Rekhavi was raised as a Rabbinical Jew and received his formative religious education at an Ultra-Orthodox Ḥeder. He studied at various yeshivoth in Jerusalem before embracing Karaite Judaism. In 1981 Rekhavi began to question the authority of the Oral Torah. From 1984 Rekhavi was mentored by the Karaite Hakham Mordechai Alfandari in Jerusalem.
Rekhavi is the Chancellor of the Karaite Jewish University based in Switzerland and a founding member of the University, which was created in November 2005. In July 2007 Rekhavi served on the Beth Din (Jewish religious court) of the Karaite Jews of America that performed the first conversions of non-Jews to Karaite Judaism since 1465. He is also the Hakham of the Karaite Jews of Europe, sits on the Karaite Religious Council in Israel, and acts as an advisor to the Karaite Council of Sages. Rekhavi currently lives in Beer Sheva, Israel with his family and worships at the local Karaite synagogue.
Rekhavi is the co-author of As It Is Written: A Brief Case for Karaism (ISBN 0-9762637-1-8).
He also produced and self-published a Karaite translation from Biblical Hebrew to English of the scriptural text read at Passover, the Haggadah.
Me՚a Shaՙarim: An English Targum of the Tora According to the Plain Meaning Hardcover – October 1, 2015 (ISBN 979-8394093548).
Yes it is. You will need to first attend a one and half year online course in Karaite Jewish Studies at the Karaite Jewish University.
In August 2022 we celebrated our first conversion ceremony here in Eglisau.
After successful completion, you will need to join us for a Shabbaton in Eglisau, Switzerland or Daly City, California.
https://kjuonline.net/learning/
Conversion is the wrong word here, affiliation is more to the point. You will also need to take part in the Karaite Jewish studies course provided by the Karaite Jewish University. After successful completion, you will need to attend a service at one of our synagogues in Israel, Europe, or the US.
https://kjuonline.net/learning/
Purim yes, eventhough it is not mentioned in the Torah, it is mentioned in the TaNaKh.
Hannuka on the other side is not mentioned in either and therefore the answer is no. As so often, people do have different takes on this matter and there are some that celebrate Hannuka. What is important though, is that if you do, do not say the Rabbinic prayer, as G-d did not command us to light the candles.