Mokou's first card is my worst on her. Her second one is simply misdirecting the phoenixes and light dodging on the red bullets. Mokou's cards are actually pretty easy overall; Ikahasa's Moon Curse and Hollow Giant Woo are probably her toughest for me, and only because I routinely screw up the second and just don't know how to do the first.
Ran is a mix of easy and hard, but you also get a lot of resources to work with (a metric ton of lives and bombs, and borders on top of it). She also has a couple of joke cards (lolWizardFoxThoughtseasiestExtracardeverlol).
Suwako, though, is entirely trick-based (except Froggy Braves the Elements). Her first card is misdirection, her second is just going up and down with very slight left or right as necessary, etc. I'm crap at Jade of the Horrid River and Seven Stones and Seven Trees, but that doesn't make them - or her - difficult. (Suwa War might, fine, but a bomb or two sorts that out all right.)