1. As far as I can remember, they don't notify you by email, (I just checked, in your account settings, there's an area where you can indicate if you want to receive emails when you receive a payment.), but they do notify you in the Itch notifications (the bell next to your avatar).
Additionally, from the dashboard menu, you can see all the statistics, including the sales you make.
2. I didn't understand what you're referring to.
3. If your game is paid, there should be a "buy now" button.
If your game is NOT paid, but accepts donations, it will say "download now," and when you try to download it, a menu will open where you can enter the amount you want to donate.
I just checked your project, and I think you're referring to "8-BIT CLASSICAL MUSIC PACK – VOLUME 1 – FOR RETRO AND PIXELART GAMES."
If that's the case, it's actually set to "paid," and if someone wants to download it, they'll first have to purchase it for $7 USD.
The box with the value is not displayed because the game title is too long and the page simply hides it.
