Yes the DCDRF are adjudicating the disputes even in case they have arbitration agreement. For instance disputes regarding excess telephone bills, though there is arbitration clause, the DCDRF are adjudicating quashing bills.
if there is a "dispute" between the parties then they are bound to go for arbitration first instead of knocking any court's door if there is an arbitratio clause. but look whther in your case the subject matter could be termed as dispute or not.
regarding converting of an unregistered firm into a ltd co. you are always free to do the same.
It depends upon the clauses of agreement. Civil Court or consumer forum will look upon the agreement and its clauses. If as per the agreement, disputant is coming under the consumer protection act and further in accordance with the provisions.clauses of agreement, the consumer forum will have jurisdiction primarily. Secondarily, if the nature of dispute is of civil nature, the civil court has jurisdiction to decide the dispute. But clauses of the agreements must be seen in the light of legal provisions and they should not be contrary to prevailing laws.