Variants / out of stock / module specific translation

-- HikaShop version -- : 3.4.0
-- Joomla version -- : 3.8.8

In our store we are selling both courses and products. One course has three different variants (with different price depending on the participants age). We can sell 12 tickets per course, and I set the stock on the main product to 12 and the stock of each variant to 0. That way, when we've sold 12 tickets (regardless of variant) the course is out of stock. But when stock = 0, the text by the "Choose option"-button change from "In stock" to nothing, and you need to go to the product view to see that it is "Out of stock".

1) Is it possible to get the "sold out"-text also in the category view when the main product's stock is zero? I'm aware of the "Hide when out of stock"-choice, but it is positive to show that the courses are fully booked
2) Since we are selling both tickets to courses AND products, the text/translation doesn't always fit both categories. Is there a way to customixe the translation for a specific product category og a specific module (like "Fully booked" for courses and "out of stock" for products)?