Two JSON Cron jobs to upload items for sale from our vendor to a 3rd party auction site and review

We are a firearms business and at this time we manually upload/post items to sell from our Vendor into a 3rd party Auction site (similar to eBay). We also review our posted (selling) items to make sure they are still within our acceptable profit margin. We'd like to automate both of these processes into a Cron job on our website server. Details: While we currently upload the items into the 3rd party auction site using their Excel "Bulk Lister" worksheet, we are setup with the 3rd party auction site to upload the items using their JSON code and REST API. We have a specific format that the "Description" of the uploaded item needs to be in. The information for the "Description", as well as other information required for the upload, is available from the Vendor's FTP server in 5 separate .TXT files; each file has the vendor SKU Item # as the primary key. Further, a download from the 3rd party auction site is needed, as well as at least one other Excel worksheet that must be manually updated; it has a table for converting the Vendor's Category ID to a Category ID recognized by the 3rd party auction site. Potential concerns/issues: (1) At this time, calculating a shipping fee to add to the uploaded item is an issue. Currently we do not have a method to evaluate weight, dimension and actual shipping (we would use an address furthest from us to keep the rate standard). Therefore, we'd like to discuss possible solutions before starting the project. (2) The "Description" is HTML code; this has proved to be an issue in the Excel Power Query that we currently use to compile the data for the upload, I do not know if this is an issue with JSON. (3) The uploaded items are treated differently for firearms and non-firearms, currently this is solved using two separate Excel Power Queries for each category. Please take your time to read through the details above, ask questions, and we will review the bids to complete the project. Thank you for your time.