Thank you for jumping in. Somehow eliminates the need for me adding this on my previous comment:
"As long as MCU is not on QFN package, it is easy."
You're now implying its TQFP, right?
Pins are "tiny" but it is possible (flux bathing in advance works wonders). E2 pin (have not gone properly through firmware, but it looks unused on MiniVan) is a usual suspect, when adding things on 32u4 boards, because is considered more accessible due to...