Dan,
Each of the object within your display can be referenced to get the components that you want. If you right click on the Gray triangle, that is left of the outline box title("Bivariate fit.......") and select Edit==>Show Tree Structure you will see all of the objects in your display. Any of the objects that you want the current settings for, you can query, such as
minimum axis = report(oo)[axis box(1)]<<get min
The assumption in the above is that you started you bivariate request with
oo = Bivariate(.........)
You can also get all of the settings for the entire display or for any subcomponent of the display by asking for the script to be returned that will regenerate the display:
report(oo)[axis box(1)]<<get script
or
oo<<get script
contained in that script will be all of the modifications your user has set.
The script results is the closest to returning all of the parameters as you listed above. However, if you have a list of the items that you are going to limit the users to, then getting the individual parameters is the easiest.
I have used both methods. Parsing through a returned script is a bit more complex, however, it does have the advantage, that once you have the script, and you make the modifications you need for the next step(if any), you can just re-execute the captured script, and the chart/graph etc. will be replayed just as the user had modified it.
Jim