Coping with loss in Panama

I will try to answer according to experience.

What are the steps to take to retrieve the belongings of a deceased loved one in Panama?

Will depend on nationality but the certificate of the death of a person is issued by Medicatura Forense (Forensics) and then registered at Tribunal Electoral.

What are the resources or specialised institutions available to assist in this process? What types of services can they offer in this context?

There are some services helping expats move the bodies. Consulate offices also help with these paperworks.

In the case of a will, how can one ensure that it is recognised and respected in Panama? What challenges arise from differences in legislation?

Will depend on proper registration. Wills in Panama must be registered properly.  If not, registered properties must go to a Juicio de sucesión and it may take like 3-5 years for it.

Who should be informed first of the death of a loved one in Panama? What are the most effective communication channels for notifying relatives and institutions?

Medicatura Forense issues the death certificate and Tribunal Electoral should register it in the case the deceased is a Panamanian citizen.

What are the implications for dependent visas, such as those for spouses and children, when the visa holder passes away in Panama? What steps need to be taken to address this situation?

Sons of Panamanians acquired Panamanian nationality.   I don't remember about married couples but I think they are allowed to stay even after death.