It’s good to hear you’ve already planned ahead for a sequel when they’re older! Consider what you want to happen in between now and the sequel- will they stay in touch until they grow up? Or will they get separated, and if so- why? Ask yourself these kinds of questions to help dig yourself out of the writers block. Sometimes you can even “write backwards”, where you start from a point in the future where you want them to be, and you just work your way back to connect it all together. Either way, I can’t wait to see what you come up with!