Hi Sam,
The short answer to your questions is yes.
Now design logic should play a factor in how you create and present your forms to your users. The ChildformDialog is basically a control that will allow you to show a modal form ex: myform.ShowDialog() it does have the advantage of allow you to translate any business object in the parent form to the child form in their current state and record positions, but as modal form it is expected to return a dialog value "OK, Cancel, etc" and this value be evaluated either in the child or parent form to do whatever your logic is.
With the above in mind, then I believe it would be kind of difficult to create a Maintenance Form (with the toolbar) and also used it as a child form, even though with creativity it can be done, you could have several New() constructors to pass parameters and either hide/show the toolbar, etc.
Also you can create Browse Dialog classes and call them from anywhere not just the maintenance toolbar.
I suggest you download the StrataFlix sample application from your "My Account" zone and study it, since it does make uses of these techniques.
Edhy Rijo