I'll give it a try, you're second hint gave me the idea of:
Luke Sky-walker - Star Wars
Possibly a star,
A Hollywood star, and for reference to Star Wars as someone who 'stars' in the movie
A monthly child.
Luke starts as a child who grows through the story.
Sometimes weighty,
Luke played some weightly roles in the Star wars saga story (sometimes), but there are many other characters that are important (although I haven't really seen it)
Sometimes liberated.
Luke was fighting against the dark side (sometimes) trying to liberate the right side. (But was initially fooled/tricked by the dark side)
Although I was thinking for more of a:
Star Trek like answer