I would advise giving your project its own identity. You're already using premade assets so you shouldn't also be using premade art and illustrations to promote your game.
I don't even know what 70% similar would look like 😅 Make it as different as possible, there are a million ways to draw a frog in pink and purple clothes. It will avoid any potential confusion or issues.
If you draw a green frog in pink and purple clothes, that's fine. If you don't copy the designs or style of the illustrations, you're fine.