How about a clan doesn't become a clan until at least four members, or some other number, are in it? That is, it can have a name, and leaders can seek to have others join, but it isn't really a clan that can make matches or anything else, until there is a minimum number of members. That minimum number could be increased or decreased, based on feedback and how it works out.
This would help those who want to offer their clans to others a way to do so.
Also, does it really make sense to have one-person clans?
A one-person clan leader could make repeated challenges to lower rated players in another clan. If only a few of the leaders accepted the challenges, the NET win ranking would be at the top of the chart, but the ranking wouldn't make any sense.