You do not need to activate bundled plugins using a key, and you can’t do it using the purchase code from the theme. As mentioned in our docs, we do not provide activation keys for plugins – https://xstore.helpscoutdocs.com/article/38-activation-and-purchase-codes . Bundled plugins do not come with personal licenses independent of the theme you purchased, read here – https://help.market.envato.com/hc/en-us/articles/213762463-Bundled-Plugins
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.