Answer to Question 1
Some of the reasons a contractor would be disqualified from a bid for not being a responsible bidder are not having sufficient funds to perform a project, not having sufficient experience in the particular kind of work, having an unsatisfactory reputation, and inadequate staff and equipment.
Answer to Question 2
The major disadvantage of forming a corporation rather than a sole proprietorship is that corporations are separate legal entities which means the only assets that are involved in liability issues are the assets of the corporation and not of the individuals working for the corporation.