Sorry for the delayed answer, but actually we can answer in the time of 24 hours, and this is a public forum, not the premium support 🙂
Regarding your questions, actually Woocommerce and ATUM stock management is synchronized, but if you want to create products directly from ATUM you can use our premium add-on ATUM Export Pro. This add-on can be used to import products or almost any data of your site using a spreadsheet. So, you can create your products on a spreadsheet, download it as a CSV, and then importing them to your site.
I leave you here the documentation of the add-on where you will find useful info about how ATUM Export Pro works: https://forum.stockmanagementlabs.com/t/atum-export-pro-documentation
And the link to the demo site in case you want to try the free trial: https://stockmanagementlabs.com/addons/atum-export-pro/
And you can always update existing products from Stock Central.
Scanning barcodes is a feature that will be available in our APP. It is already developed and we are doing the tests to release the beta version soon. We will let know our users when this happens.
Hope this helps,