Is it ok to use this name "Musfira" to a child? while we know that it is only Allah who know about the child's future. isn't it like predicting future if we put this name musfira(bright face of a true believer on the day of judgement) ????

Musfira has a general meaning and not specific to the Day of Judgment. It means radiant and glowing with happiness. The Quran uses it to describe the faces of the virtuous people on the Day of Judgment, but it still an attribute, and it is not like predicting the future if you use it.

The Quran uses other words like Naima (soft), Radia (happy and content), Nazira (glowing and radiant) to describe the faces of the believers on the Day of Judgment, and this doesn't prohibit their using them as names.