Hi,
1. Try to disable Use images from product variations
option in Theme Settings -> Shop -> Attributes Swatches.
2. Could you please check is your price problem related to our theme? Try to switch to default WordPress theme and compare how it works.
3. Additional information tab is generated automatically and you can read how it works in WooCommerce documentation https://docs.woocommerce.com/document/editing-product-data-tabs/#section-6
4. Countdown timer works with simple products only. The problem is that variable products may have a lot of prices with sales (for each variation) and in this situation, it is not possible to get the exact date when the sale will end.
Regards