Is there any way to set the startup page in Thunderbird to be the latest mail instead of some link?
I've found a fix!
You need an add-on to enable this functionality (which is default in Apple Mail and Outlook...)
It's called Select Inbox and you can download it here: https://addons.mozilla.org/de/thunderbird/addon/select-inbox/
Once installed, go to add-ons -> select inbox -> options and select first/last.
Yes. In the menu, choose Edit > Preferences. It's the forst setting on the first page, called something like Thunderbird start page. (I'm not using English so it might be slightly different, but you'll see it).