Hi there,
I’m afraid not – the login/lost password pages are WordPress territory, and WP.org wouldn’t allow the theme to alter any of those pages.
You can always do some searching around on how to alter these pages.
For example: http://wordpress.stackexchange.com/questions/133647/how-to-redirect-users-to-custom-lostpassword-page
As for the multi site issue – this is something you may want to ask on a site like stackexchange (linked above), as I don’t know too much about multi site.
Sorry I can’t be more helpful!