Basically, we pretty much do not know anything about these people.
Will they be a risk in the future?
Basically, we pretty much do not know anything about these people so it is very hard to say. It also depends on what you mean by a threat..
A threat from their ideals? Can it be much worse than the monetary powers who are already present?
A market threat? Even "large" holders will struggle to influence the market, every large spike gives a redistribution of wealth. Those people who were holding a lot of coins generally sell when they see an opportunity. People wont sacrifice their quality of life for money.