Yeast is what makes real Kolsch beer. You can only brew true Kolsch if you ferment with Wyeast 2565 or WLP029. You can get away with Wyeast 1007 as well. Everything also doesnt even come close in taste and flavor department. With US-05 and cold conditioning you will be making nice blonde ale definatelly not Kolsch.
Using identical grain bill, hops and fermented warm (65-70F) with Wyeast 2565 and NOT cold conditioned it still will be much closer to original than one fermented cold (60-63F) then lagered for weeks with US-05. Kolsch yeast produces unique chardonnay-like charachter which you not going to get from any other yeast no mater how hard you try.
I find simplicity and patiance is a key to brew really good Kolsch. 100% pilsner malt (forget about wheat if you want it to be crystal clear and crisp), only 60 min hop additions to around 20 IBUs with Saaz, Tattnang or Hallertauer, ferment around 60-63F actual wort temperature, and then lager it for month below 40F. You will be rewarded with results.