Hi,
I'll let Xavier answer to you tomorrow regarding the "item no longer sold" issue with the wishlist as he is the specialist on the wishlist.
Regarding back in stock notifications, that can be done with the waitlist system in HikaShop. You can activate it in the Display tab of the configuration and that will add a "notify me" button on the product page of out of stock products which will then ask the name/email of the user.
You will also need to configure your cron task in the configuration as that is required for the waitlist plugin to check periodically the stock of the products in order to send the notifications when needed.