Legal Question in Real Estate Law in California

No, you can have a vested contingent or future interest that may or may not mature into ownership at a later date. There are also present interests that may be vested but are not ownership - such as leaseholds, easements, and life estates. Without context it is impossible to answer your second question.

Further, you can be vested but only be a part owner, as someone else's tenant in common, so you might be vested but only own 50% (common) or less than 1% (unusual).