Hey there, this is my first theory craft on using Secret Rogue in Wild. The main way for success is using the power of Hanar as well as the value from your other minions to keep your opponent from getting any presence. Highlander cards are very powerful in there own right and can always find a way to give you major value in the late game, especially with Spirit of the Shark.

Here's my general Mulligan list,
Always keep:
Shadowjeweler Hanar-This card is essential to giving you the value for this deck to win, with things like Bamboozle being able to evolve cards that other secrets summon and just a great 1/5 body on turn 2 that will most likely survive.

Clever Disguise-Another card that gives you good value as well as another way to generate other secrets. This card is very helpful for generating value for you early and midgame to help you start pushing for the endgame.

Secretkeeper-Any good Secret deck needs this card to start buffing until your opponent has to deal with it. Growing pressure is very scary especially if you can start chaining Secrets with Hanar, so try and get this card in your hand as soon as possible.

Secrets and Cards to keep with them:
Bamboozle-At first I thought about this being really bad with Hanar, but then realised that the minions other secrets summon are really nice to evolve into 4-5 drops early game. Keep this if you get any secret synergy at the start.

Dirty Tricks-This card is a very nice early game trigger that can help you find cards to push you through the game faster. Most games have at least 1 spell trigger by turn 3, so getting hand advantage early is very helpful by punishing your opponent.

Blackjack Stunner-Best 1-Drop in your deck. If you have this and a secret, keep them both and really slow your opponent with the targeted Freeze Trap. It's also good late game so if you don't have any synergy with it, it's fine to throw back in for a late game removal.