As you've guessed, these frames were sold under several brands. Manufactured by Hodaka, they were sold under their in house brand Fastrax, as seen on the original rear shock you have there. There is a little history of Hodaka and Fastrax here
https://www.fastrax.com.tw/
The frame number may be on a sticker under the carbon main frame and I'd guess starts H7. Please let me know what it is if you can find it.
The Fastrax bikes were either called 'Magnum' or 'F1'.
In the UK, Coyote brought in several generations of the Hodaka frames. Yours is the first version. I've got both an F2 and a DH, pictured in my thread
https://www.retrobike.co.uk/threads/coyote-dh.421541/
The Koga-Miyata branded frame was the same, but whereas the Coyote/Fastrax frames were the same colours, the Koga-Miyata had their own scheme. See the thread
https://www.retrobike.co.uk/threads/koga-miyata-sky-expension-1997-downhill.168576 for example.