MarketPress Global Categories + MultiSite

Hello,

Q1. I'm trying to achieve a uniform tree of categories any seller can use to add products. Sellers can not create their own categories, they can only use the ones provided. I used the following post to take care of this: https://premium.wpmudev.org/forums/topic/global-product-categories-solved-a-tutorial?dsh=1&utm_expid=3606929-40.lszTaIEzTbifDhvhVdd39A.1&utm_referrer=http%3A%2F%2Fpremium.wpmudev.org%2Fforums%2Ftopic%2Fcategories-in-marketpress-with-multisite%3Fdsh%3D1

However, updating the blog template adds new categories only for future sites, and not the ones already created. How can I get all sites to receive new categories once they are created and/or updated automatically?

Q2. Is there a way to load many categories at once? Like the Google product taxonomy list
https://support.google.com/merchants/answer/1705911?hl=en

The latest on it seems to be this post, but I could use more info on it: https://premium.wpmudev.org/forums/topic/common-large-category-structure-for-multi-site-marketplace

Thank you,
Nick