All investors who buy during the ICO have the same risk. I think, bonuses are nothing more than a marketing move. After listing on the exchange, the risk is significantly reduced.
In theory, these bonuses should at least slightly ease the risk of investors. When all teams of projects work well, there will be no need for these bonuses. Investors will buy tokens without them.
Probably yes. Therefore, bonuses are unlikely to reduce the risk for all investors. Of course, it can be precisely stated that the first will have more profit.