Hello,
- "last card" : this hint points towards the sheep's recipe. It was "Sheep recipe" learned via same quest as in story, yet i disabled it (to not repeat the same one twice), the recipe was supposed to be in a treasure chest. I just checked and there's no treasure chest with her recipe (i'll add/fix this in next update v1.4), for now you can buy the missing recipe from Black, interact with her tap Q several times until you get to the recipes, then select the desired one and purchase it. If recipe learned, Blacksmith won't give this tip anymore.
- "futanari" : yes, in story Nishy turns futa once (as a sneak peak for the future). In Free mode she can go futanari on will by taping F key. You need to unlock this first tho, SB Reputation to be 100 or above. Check for details in the Book at the Free Mode's main quests, in their description you can find what unlocks at which point.
To quickly increase SB reputation you can do : SlutJob (walking naked + slapped-raped) combined with selling milk cups (free ones give more sb rep). Quick tip : level up the bar to also get more money from selling milk cups.