While Evelynn isn't very good at early game ganks, the new dark harvest gives her some more freedom to gank whenever she feels like it since it doesn't have a timer. If you need DH stacks early on, it wouldn't hurt to just apply some pressure to lanes. Even though you might not kill them early on, you'll likely be able to get them to half health for the stack.

In terms of DH or Electrocute, both of them work well for Evelynn. Electrocute provides consistent damage throughout the game, while Dark Harvest compliments her as a scaling Assassin. While I personally find DH more fun, Electrocute is completely viable on her, and is better than DH in some cases. TL:DR, Electrocute for consistency, DH if you think you're gonna stomp.

Thanks for the feedback! Evelynn is initially described as an entity, not necessarily confined to any form or gender. The reason that Eve chooses to appear as a female is because that is the best way to lure people to massacre them. Eve can take any form "she" wants to, but she has the most success in the female form