These are, as you have said, two simple methods all you need to do is to have the option on your web folder to get forward the not found errors to a default page. You can put in the entry on your .htaccess file.
There are real simple and and effective.
As for the second option, it is quite simple and you can set priority of the default file that could be displayed on the web via defining the same in the respective folder or the webroot. The entry for this comes in the .htaccess file.
I hope this helps.
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