Nice photos Buzzlatka! I also used Peltors for both young'uns up to about age two. One each in pink and blue "kids" style. I find they come in very handy for lots of noisy situations. I keep them on a peg in the shop next to my own when not flying. My kids like the colors, which helped get them to wear them.
Earlier I tried a product called Earplanes. They are reusable silicone earplugs with a porous ceramic core for equalizing pressure. They come in Jr and Adult sizes. Well-made, but I can't say that they were ever a big hit with my kids. As far as ear plugs went, cotton balls were tolerated much better.
This is all in relation to my humble O300A. When going out for an hour behind an IO540, say, I give them the Zulus, and wear the backup headsets myself. Now that they're a bit older, it's fun conversing about the sights and the control inputs.
As for equalizing, nursing is about the best ticket there is. Pacifier probably works the same. I bet you'll find that she falls asleep pretty darned fast and stays asleep at least until the descent, if not the roll-out.
There are some good threads dealing with child seats, and altitude considerations on here as well.
Best wishes for the new family!