No. The icons are integrated directly into the firmware of the bracelet and no third party application can add them.
Only Xiaomi can add them into the firmware and if they do, we'll always update our application to give you all the great features like multi-line text display. Please do not down-rate us or ask us to add icons. It's truly not technically possible.
Current Mi Band 3 firmware does not have the classic icons integrated into the firmware and therefore you can not select them in our application. We believe that this is a bug in current firmware introduced by Xiaomi and we're sure that Xiaomi will fix it in the upcoming firmware updates. We'll update our application every time new firmware is released by Xiaomi and we'll include every single icon available inside of it for your selection!