Can a guardian make financial decisions without the conservators consent?

This is where it is important to get your ducks in a row. Consult a lawyer that specialize in estate planning. Don't wait until it is too late. At 71 my trust, guardianship, and affair are in order. I did this almost 20 years ago. I meet with my attorney about ever 2 to 3 years to make sure the laws have not changed.
You can become ill any moment, you can die any moment, we are not immortal. Plan ahead.

Yes, sunflo. Many times a single guardian will handle everything.

Can guardian and conservator be the same person?

A guardian of the body must work with the conservator to finance what is to be done. For example, the guardian may want their charge to go to a ritzy retirement village, but the conservator will say no, to find something less expensive. Compromise and coming to a meeting of minds between the two are called for.

the Guardian of the person makes healthcare decisions, such as the need for home care or skilled nursing care. The conservator is responsible to pay the agency or nursing home. They have totally separate jobs. In the event of serious conflict a good judge will remove one or both of them.

The conservator must seek court approval for transactions such as the purchase or sale of real property, gifting of assets or engaging in estate planning for the protected person.

Guardianship law varies from state to state and with the court's guardianship order. A conservator is usually the guardian of the estate (money and property) while a guardian is the guardian of the person. Check the actual court orders and, if this does not clear things up, talk with a guardianship attorney in your state.