I can't see how you could have oil leaking from the turbo, even if you did overfill the oil, it shouldn't leak there. If you started it up while it was overfull then you could get that symptom, but once you drain it and set the correct oil level it should clear. The only think you say you did was do an oil change and bam! you have blue smoke that you didn't have before. An oil change won't do that on its own. You could have blown the turbo seal, and the other turbo could also have a blown seal as well, but that is a long odds coincidence. And oil in the spark plug wells???? you haven't cooked the motor have you? a cracked head could do it.
I'd be rechecking your oil level and making sure it is correct first, and assume that the oil in the spark plug wells is spill from when you filled it.