For starters, if all you need is sheer coverage, you can apply mmu with a sheer coverage -- just use a fluffy powder brush instead of a kabuki (the fluffier the brush, the more sheer the coverage) and make sure you only have a tiny bit of powder on the brush before you apply!
That being said, I would think that it would be better to match your neck, so you don't have a noticeable makeup line at your jaw. I think a makeup line there would be more noticeable than your ears being a different color!
I've noticed that most of my face (my nose, cheeks, and chin) are more pink than my neck, while my forehead and jawline are more yellow and are closer to my neck color. For a while I tried foundations with pink undertones since that's what the Prescriptives sales associate matched me to, but I always had a noticeable pink makeup line at my jaw! Finally I found a mineral makeup that is a perfect match for my neck and forehead color, and it also helps hide the extra pink on the rest of my face, so now my whole face is the same color as my neck! My mom is always telling me that my makeup looks soooo much better and more natural now!