Here are Plugins & Snippets collection of downloads related to Commissions. Please have a look if there's any download that could be of help to improve and enhance your Easy Digital Downloads WordPress webstores.
Payment of Vendor commissions – automatic payment of vendor commissions can be fully automated when using tools such as PayPal Adaptive Payments which splits revenues instantly between the platform operator and the third-party vendor. Tools like this avoid a lot of administrative work and save huge amounts of time.

[1] How to Build a Digital Product Marketplace in WordPress - Plugins & Snippets

[2] PayPal Adaptive Payments plugin