All those suggestions are great. Alot of kids like it if it's something you do 'together', both of you brushing your teeth at the same time. Just let her chew it (without toothpaste). Singing is a great idea, I have a great teethbrushing song (I know, how sad LOL!), just make something up about brushing, I'm sure she'll love it! Make it a fun thing, but don't get too worried about it, she'll let you in when she's ready. It's more important to worry about diet than brushing at this young age.

Hope one of the ideas helps!