Is it possible to specify tab order on the product page?
Yes, it can be possible by Priority field.
Is all tabs will be shown on the frontend product view page?
Tabs that matched Conditions will be shown on the product page. It also depends on the other fields like Status, Website, Customer Group, From-To, Discard subsequent tab.
From where can I get the Extra Order & Product Fees extension?
You can get the Extra Order & Product Fees extension from here https://magediary.com/extra-order-product-fees-for-magento-2.html
What if product tab not showing on the frontend after add or edit?
If the product tab is not showing on the frontend after add or edit, then do reindex by run the below CLI command php bin/magento indexer:reindex product_tabs_rule
Is all assigned accessory items will be shown on the frontend product view page?
Yes, all selected items will be listed out on the frontend product view page. The customer can choose as many items as they want by selecting multiple checkboxes.
Can we show the inquiry form only on the product or category page?
Yes, set the Enable for Product View and Enable for List View fields accordingly under the Permissions tab. Reference guide: https://magediary.com/docs/product-inquiry-support.html#permissions