Is it permissible to continue working for the company and donate the proceeds from the second level to the needy, while clarifying the Shariah ruling to those invited to register, knowing that the company requires both the first and second levels to begin working?

It is not necessarily true that the company's commission to the subscriber for those registered in the second level is part of their wages or an unlawful appropriation of their money. However, if a portion of the subscriber's wage is contingent upon this, then ambiguity arises, and uncertainty (gharar) enters the transaction, making it impermissible for that reason. It is not permissible to enter into a void contract, as it is forbidden. But if these rewards are not taken from the wages of those registered in the second level, nor are they part of the subscriber's wage, but rather an incentive bonus, then the company has the option to grant or withhold them, and there is no harm in that.