No, I didn't succeed in encrypting the device and still using fingerprint afterwards. I even tried encryption with a "graphic" gesture before this kind of password was suggested by blackview_admin. Directly after encryption everything works fine, even fingerprint reader and all the settings are available. But after next restart all settings and functions related to fingerprint are gone. Therefore I know it SHOULD work with Android 7 but some kind of stupid bug in blackview firmware kicks fingerprint out of the system.
Currently I'm using BV8000 pro without encryption even if I really would like to encrypt the whole device.