Hi, just wanted to let you know, the Frog_Health plugin is not possible to use for extra skill resources at the moment. I read through the forum on RPG Maker forum, and the last message from FrogBoy for the plugin was Dec 2018 where they mentioned that this is in the future plans, but it seems that they have at least temporarily stop further development (last message was Nov 2019 answering some questions on the plugin).
NeMV has a plugin that might work, but it won't show on the status screen or battle window from what I can tell, and they have stopped maintaining it since 2017 as well.
So...you're my only hope for now, huhuhu. This is a great plugin regardless, and thank you for making it, cos it's incredibly user friendly.