I can't answer to the best way to introduce the queen, sorry. As for the brood, the queen you're saving is already laying, right?
I like the idea of frames with more larvae and capped brood than eggs. I've had bees decide they don't really like the new queen and start emergency supersedure cells from the eggs they already have. Not sure it it's because of the abrupt change in pheramones or if there was something wrong with the queen I'd ordered, but it's something to keep an eye out for if you really like the queen your saving.