I mean you would be inclined to say Gaga after AHS, GG, Oscar nomination, soundtrack single, countless tributes, Woman of the Year 2015.
But the last receipts don't lie tho, I thought Gaga was more popular than Katy but it looks like it's not.
I have to go with Katy now. What do you think ATRL
The things you mentioned in the OP are not common knowledge for 90% of the world's population.
Seeing as Katy's music gets more reccurrnt airplay, streams AND sales ( didn't Firework went up in the 80s on iTunes last week?) I think it's safe to say she is more popular.