I'm starting a game with a boy/girl option (like pokemon) but I need the hero to start out invisible. I tried to use the change sprite association (to a blank hero) but there's always a lag in between the title screen and the start of the game in which the player can see the hero before the sprite change.

Start without anyone actually on the team, once they choose boy or girl you add the party member, if you have two sprites depending on if it is male or female, then change that before you add them to the party. This should resolve your issue.

I have two different solutions for you:
1. Initialize in the database for the character in front to a blank charset and then change it back later when they need to be seen.
2. Hide the character in front behind some tiles that will obscure it completely.

Both are fairly easy to do so you can use either method to get the results that you want.

Thank you everyone! :3 This has helped me a lot!

Solution #1 was what I was suggesting, thank you for explaining it in an easier to understand way. I was not focused when I wrote that.

One of the neato torpedo things I do is using the "hero" as an actor sometimes..
you can use Panning to keep that fact hidden and can make the hero look like anyone you want.