From the doc,
h = biplot(coefs,'Name',Value) specifies one or more name/value input pairs and returns a column vector of
handles to the graphics objects created by biplot. The h contains, in order, handles corresponding to
variables (line handles, followed by marker handles, followed by text handles), to observations
(if present, marker handles followed by text handles), and to the axis lines.
So, save the handle and retrieve the various handles from within and set properties of them as desired.
Just a vector of handles isn't all that convenient a form in which to return the information although know the number of variables and components to be able to count...
