Sorry, but the order isn't relevant:
I looked at your tests and the order is relevant when you have only one pen drive: (default ext, SD, Pen Drive). Can you limit your application to just use one pen drive.
1. inner memory + sd card:
/storage/emulated/0/Android/data/com.misiolvas/files
/storage/3E98-DF1D/Android/data/com.misiolvas/files '<--sd card
2. inner memory + sd card + pendrive1
/storage/emulated/0/Android/data/com.misiolvas/files
/storage/3E98-DF1D/Android/data/com.misiolvas/files '<--sd card
/storage/424610224610196D/Android/data/com.misiolvas/files '<--pendrive1
5. inner memory + pendrive2
/storage/emulated/0/Android/data/com.misiolvas/files
/storage/6C4A-711A/Android/data/com.misiolvas/files '<--pendrive2
Your original question was: How can I identify which is the sd card and which is the usb pendrive (3E98-DF1D/424610224610196D)?