Fix Wordpress Problem

I have a website Wordpress website that has recently been made into a multisite to accommodate another language (the original site is in English, the new site is in Dutch).

I have three issues:

1. Currently I can't edit the new Dutch language pages. They are showing fine on the live site, but each time I try to edit one I get an error saying "You attempted to edit an item that doesn’t exist. Perhaps it was deleted?". This needs to be fixed.

2. The way to switch between the two languages is via a fixed bar at the top of the site. This bar is different on each language (the Dutch site is a blue bar and the English site is a black bar). I need the bar changed to a subtle pale grey, with smaller text aligned to the right. This bar has to be the same on both sites (or, if anyone can instead add a flag icon above the search box in the header as a way to toggle between the two languages, so I can remove the fixed bar at the top completely, that would be even better. Please mention in your bid if you can do this).

3. The favicon will show when you're in the WP dashboard, but it's not showing on the main site. Currently the Genesis theme favicon loads. I need this fixing.

I need this all completed in the next 24 hours. Please only apply if you can complete this work by 16:00 GMT Sunday.

I will provide WP and hosting login details immediately to the successful candidate..