Luke has to face Vader to make the movie exciting. Yoda knew this.
As for the plan to rescue Han, it was a masterpiece of subterfuge, akin to Inspector Clouseau's ruse of being an idiot, all the while brilliantly hiding his cunning genius and luring Jabba out into the open. Yoda's training made it all possible... he used the Jedi mind trick to get Jabba to take them to the Sarlacc pit. Isn't this obvious?