Whatever the view roles for the page that contains the forums instance are will also be applied to the supporting pages of the forum.
" I have set the Page settings to http://10.51.108.50/CADRMS/Forums/ForumView.aspx?pageid=46&f=2~1 are set to All Users"
That is not possible, you cannot set different view permissions for supporting pages like /Forums/ForumView.aspx they inherit the permissions of the CMS page (ie forum.aspx which is the cms page containing your forums) based on the pageid included in the url.
Nothing about parent child relationships controls the roles of a given page other than if the user does not have view permission on the parent page then the child page will not appear in the menu for that user since the parent page would not be in the menu and the child page hangs from the parent page, but a user could still access a child page directly by url so long as the child page view roles allow it.
Forum admin links are only available to users in edit roles not view roles so you don't need to worry about that. For users to access your forums you must give them view permission on your forum.aspx page.