Answer to: change 128 GB SSD for the 256 GB SSD (11" Air)Yes. I have successfully done the swap and there are no issues with the physical size of the drive. Just make sure you have the correct Torx Security size (which is T4 and not T5).
Answer to: Are the 2010 MacBook Air 13" and 11" memory cards interchangeable?The short answer, yes they are interchangeable. Both machines are running smoothly with no issues whatsoever.