Thanks for posting interesting info. Supervision brand was/is owned by Dar Yar as well as their partner company called Sperry. They dealt with not only Famiclones but also PC Engine clone and even MSX cartridges, but I've never seen their activity related to C64/128!
Watara Supervision related to Supervision?
As far as I see there's no relationship between them. Supervision mentioned above is from Taiwan. On the other hand, Watara Supervision was created by Fixtron from Hong Kong. More correctly Supervision seems to have been manufactured by a partner company and their joint venture in mainland. Dar Yar had their own partners in Hong Kong and mainland, but they were different companies.
Fixtron registered Watara trademark in North America and West Europe.
Their Chinese joint venture registered Watara/Travelmate trademarks in mainland.