Welcome to the forums. I don’t think there is any way to do this the first time as the installation would require you to load a Linux system to start the installation and this would almost certainly not be running Orca. Once you have installed openSUSE, you would never need to reinstall because you can upgrade to the next version using the command line.
Yes, but that won’t help this user get openSUSE installed. As far as I understand, the openSUSE installer does not have assistive technology implemented that would help visiually-impared users to install this distro.
It is something that would need developer attention ie our YaST developers in particular - perhaps subscribe to our firstname.lastname@example.org mailinglist and make such a request. I think it is a good (and important) idea, but I’m realistic enough to know that such a project would not be trivial and would require additional resources to implement.
And also, once OpenSUSE install, can we use Orca?
Yes, I believe there is active development for using Orca in both the Gnome and KDE desktop environments.