Is self-ownership the same as economic independence or economic security?

No.

They are related but different.

Self-ownership primarily concerns:

control over one's own person and labor.

Economic independence means:

having sufficient economic resources to avoid substantial dependence on another person's resources.

Economic security means:

having sufficient and reasonably stable resources to meet one's needs and withstand economic difficulties.

For example:

A person may have self-ownership but not economic independence.

A formerly enslaved person may legally control his or her own labor but have no land or capital and therefore need to work for someone else.

So:

self-ownership is not economic independence is not the economic security

although they can reinforce one another.