In terms of how to play the deck, the plan is generally to control the board early on, putting on as much pressure as possible, and using cards like Face Collector, Blink Fox and Tess as value generators to prevent you from running out of steam: the name of the deck and the your game-plan is Tempo. You want to keep your opponent on the back foot as much as you can, using cards like Vilespine Slayer and Sap to slow them down, and then finish them with Cold Blood (this doesn’t mean that you shouldn’t consider using these for favourable trades) and Leeroy Jenkins (or Reckless Rocketeer, in your case).

The Pick Pocket substitution, as you said yourself, is not what I’d call optimal; you’re substituting two threatening minions with card generation cards that do nothing at all for your board presence: you should probably try replacing them with other 3 mana threats, possibly such as a second SI:7 Agent, or potentially Marsh Drake. One Pick Pocket could be added if you find that you do regularly run out of cards, but I’m not sure how much of a problem that should be for you.

Hopefully this helps 🙂

What archetype?

Yeah, but is it still playable without him?

How necessary is hemet in this deck?

Do what you like, but Aspirant is definitely good and worth the spot in this deck.

Replacement for twilight guardians? :/
Was thinking maybe sen’jin as a direct replacement?