The translations in your first screenshot do work, the problem is probably in whichever way you tested it. For a proper test, you should have Qt Linguist and gettext installed, run "make rpm", which also generates the translations files from po files, and install the resulting RPM. This might not work on the device (gettext too old?), I make the RPMs on my desktop Linux system.
The time remaining ("1 h 34 m / 1 h 34 m") is used for brevity. "1 h 34 min / 1 h 34 min" would be split across two lines, at least on the Jolla 1 screen. I'm open to better suggestions.
TThe navigation instructions come in most cases from the provider APIs. The providers don't support all languages. Mapzen supports cs-CZ (cs), de-DE (de), en-US (en), en-US-x-pirate (pirate), es-ES (es), fr-FR (fr), hi-IN (hi), it-IT (it) and MapQuest Open en_US, en_GB, fr_CA, fr_FR, de_DE, es_ES, es_MX, ru_RU. OSRM is English only and Digitransit translated as part of Poor Maps.