Can all ants morf in to queens?

Definitely not.

In most kinds of ants, if you feed one of the larvae the right amounts of the right kind of food and hormones, then it will grow up into a queen. Otherwise it will grow into a worker or soldier or some other caste. Once that has happened, in fact, by the time it forms a pupa, it is too late to change anything.

A few kinds of ants form only small colonies and they do not have proper castes at all. Most of their females may lay eggs, and if the main egg-laying females die, then other females can begin active egg laying.

However, some castes of many kinds of termites (they are not ants, but form similar colonies in much the same way as ants) can morph into queens if the real queen dies. The morphed queen is never as big and effective as the original real queen, and it may take several morphed queens to do the job of one real queen.