A consent order has to have the agreement of both parties. You can withdraw consent.
If there has not been full financial disclosure, that would potentially allow for the order to be overturned even if it was stamped by the court. It depends on whether the disclosure would have made a material difference to the settlement.
Have you had legal advice on the proposed settlement? It is impossible to comment on the fairness or otherwise of it without knowing more about your respective assets, incomes, ages, length of marriage, children etc
Child Maintenance is based on your income and is a statutory requirement. It does not need to be in an order unless the amount is much higher than the amount you would be assessed as having to pay. In any case the child maintenance
element of the order is only valid for 12 months. After that you can ask for a cms assessment and revert to statutory minimum.
Your CM assessment will also be affected by the birth of your new child. You should speak to CM options about how to handle CM given your proposed paternity leave.