The way I would say it is "In the film Mickey is smart, funny, and brave." As a native speaker, it sounds more natural to say "smart, funny, and brave" rather than "funny, smart, and brave," but I can't express why this is linguistically.

Yes it is grammatically correct. Because Bruce Lee was an actor, it is better to say "Bruce Lee starred in many action films" or "Bruce Lee acted in many action films."

An overdose is an excessive and dangerous dose of a drug, so the phrase "for a long period of time" doesn't make sense in the sentence (although its grammatically correct). The correct way to use overdose is: Doctors advise patients not to overdose on vitamins. Notice that the construction is always overdose + on + (something). Overdose can also be used as a noun. For example, many people who overdose on heroin require immediate medical attention. You can also use "to not" instead of "not to" for the same meaning. "Not to" is slightly more common.

"Someone joined the search" is more common than saying "someone joined in the search," but they both have effectively the same meaning. I can't think of any cases where they don't take the same meaning, but there is a subtle difference that I can't quite express.

Hi! I just listened to the song and translated the first verse and chorus. Let me know if you need help understanding. --- (I can't understand the first part of this line) ... I know its true When the going gets rough and you feel like quitting she'll see you through When the woman you have can make or break you, it happens everyday She'll be your helper and stand beside you so listen to what I'll say You need a woman that will help you with everything you do If she has backbone instead of a wishbone you can't lose I said a backbone instead of a wishbone yea A backbone instead of a wishbone yea A backbone instead of a wishbone yea I said now a backbone instead of a wishbone yea