Yoast should get all the same schema that GeneratePress marks up by default – there shouldn’t be anything additional you have to do. Which text attributes are missing?
Ah, I see. I’m not sure if it’s possible to merge the two, unfortunately, as we use microdata and they use JSON+LD. You might be able to contact Yoast to see if there’s a way to hook into their output to add the text items. I did some searching through their documentation but couldn’t find anything.