Agree. Just adding another comment so hopefully OP sees it. ESH, though OP less so.

The monetary demand is clearly asshole behavior; but OP is also being weird about the items for mom, and the shower for the second child.

Where I come from, a shower for each child is expected. In that case you pay MORE attention to the registry, because mom probably already has a crib/stroller etc. so you want to get things that are actually still needed (like blankets that haven’t been thrown up on, onesies that aren’t pooped all over, gender specific things if you care about that etc.).

There is absolutely nothing wrong or inappropriate about a mother putting necessary items like nipple cream on the registry. In fact, most of those type of gifts go over fantastically at a shower.

The last shower I attended, I bought all gifts centered for mom. A comfortable delivery gown that’s nicer, cuter, and more comfortable than what the hospital provides. Nursing pads and balm. A gift certificate for a post natal massage, and a bottle of wine for her first post baby drink.

Moms get largely ignored at showers, and it’s a nicer gesture to acknowledge the pain/struggle of new motherhood and delivery than buy another onesie that will immediately get ruined when she’s already going to get 400 of them that the kid will grow out of within a month.

Also - don’t buy newborn sizes. Everyone buys newborn sizes. If you’re doing baby clothes, pick a random size that they can use down the road. Several of my friends had larger babies that didn’t fit into newborn sizes for long, and had to donate almost every outfit they received at the shower.