Yasuo has a fairly strong early game, particularly levels 1 - 2, its hard to scrap him due to his high melee range, attack speed, base damage on his E and ranged power of his steel tempest.
He'll be fairly predictable with his E's level 1 he's likely to use it for last hitting so if you time it right it'll be free shurikens, typically i prefer just farming till level 6 because yasuo's power drops significantly mid game.
Keep in mind he has no mobility without an enemy creep wave, so if he clears the wave when you're 6 and you're about even, ult his ass and kill him. (obviously you also need to assess the situation to not get baited in to a gank or get hit by his ultimate)
Also try to stay away from your own creep waves, not only does this make it harder for him to disengage when trying to trade but it also prevents him from dashing to a creep next to you and getting a free steel tempest off.
I suggest finding a friend who plays yasuo and practice against him, buy yasuo yourself and play him, figure out his weaknesses.
As for le blanc, all you really have to do is dodge her harass combo, either by predicting when he's going to W on to you with sigil or reacting to it, mostly I actually shadow on to his original location so that if he ports back i can hit him with my autos for a better trade. You'll want to ward before being this aggressive though, mostly its ok to just shadow backwards and shuriken his original location cause he's probably gonna port back to it (Lee syndrome)
As for when you get your ults... I'll be honest there are like, 10 different ways this could really go, probably more but don't be concerned really, as long as you don't eat a chain, you should be completely fine, you can also dodge a lot of her damage with your own ult, just don't let him bait the ult out of you, bide your time, wait for him to all in you, or for him to use his mobility. Typically by this time you should be easily harassing him though and walking to roam else where (its really hard to kill good le blanc players as zed).