Glad to see "trousers" accepted - pants in UK means underpants!
Mm, but I'm still doing it from word boxes and do not have the choice of trousers. A word box for trousers needs adding.
No, only the main translations have word tiles, that is how Duolingo works.
If you're using Duolingo on the web, you should see a "Use Keyboard" link toward the bottom of the screen; I don't know if that's available in the apps, though. But if you do see it, you can switch to the keyboard option and type anything you want.