Yes, the second error I think is because I'm trying to assign a
control_mode_statusConstPtr& to a control_mode_status. Which brings up
another question, and this may just be my inexperience with C++ but,
how can I get a (copy of) the control_mode_status message itself to
assign to my data member?

Same way you dereference any pointer:

var = *msg;

const std_msgs::StringConstPtr& msg = event.getMessage();

(note the &), as in the example in the docs? Is it a typo?

Sorry, that was a typo in my email. That works fine, and is correct.

Josh