Standard and hard have almost exactly the same requirements... the stat requirements are just higher on hard. As long as you're raising friendship with both of them and raising confidence and gamingness, it should work. (You also cannot have threesomes with Nate and Dan, and you must talk to Nate about sex and intimacy, but those requirements are the same between standard and hard.)

The other thing to watch out for is that you raise your friendship with the two of them somewhat evenly... there's a check on standard and hard (that's more stringent on hard) that will break them up instead if one of them likes you significantly more than the other.

(In terms of numbers for hard, you need at least 50 friendship with both, at least 40 of gamingness and confidence, and the friendships cannot differ by more than 24)