Cold can make you miserable. I think a lot of folks sleep colder than others. Especially some women. But in reality many men are the same.
I find late Februray or early March a great time to take new folks out to try winter camping. Not because it won't be as cold. It might or might not be. But because of the additional amount of sunlight. When it is dark by 16:00 it makes for a long night. Especially with no available fire wood. Perhaps a recon trip prior to the overnight to find and stash some wood.
I think being acclimated would help too. Spending as much time out doors as possible prior to the trip. The body tends to adjust to its environment.
Cheap fixes, Many you already did.
Hot water bottle in the bag. Or a few of those chemical hand or body warmers tossed in. They work by the fire as well.
Not a hammock guy so no feedback there.
If on the ground in cold weather, closed cell pad, then another thermarest on top of that. I use a Big Agnes insulated air core on top of a cheap blue closed cell pad. You use some acronyms I am not familiar with.
I am a tarp guy, I like the air movement. Many folks like the still air of a tent. Especially if there was no fire to look at. A fire not only warms the body, it relaxes the mind.
Hat or balaclava, is a must. You mentioned dry socks, also a great idea.
If you have good ground/bottom insulation and still have to wear a ton of clothes in the bag to stay warm. You need a better bag. It doesn't matter how you sleep in it. It matters how she sleeps in it. Also try not to breathe into the bag. It just wets the insulation.
If your not in bear territory, a thermos of hot chocolate can add some heat and calories in the middle of the night. Wake up cold, slug down some cocoa and go back to sleep rewarmed.
For the feet. I use and recommend Steger Mukluks. Hands down the best foot wear I have ever used for cold weather camping. You can even get them in some fashionable ones now for the young lady. I use the Arctics. Buy an extra pair of felt liners and use them to sleep in if you really need to.
http://www.mukluks.com/
When in extreme cold we use this drink called "The Northwest Passage" basically instant hot spiced cider with Butter and brown sugar melted in. Plenty of carbs and fat to stoke the body's furnace to help it keep itself warm.
Merino wool on the inside and middle, then add an outer insulation layer and a wind shell. Top and bottom
Wintergreen Northern Wear makes some great winter pants and anoraks. They are not cheap. But my Anorak is over twenty years old and still has much life left in it. Same for my shell pants.
http://www.wintergreennorthernwear.com/
As was already pointed out, do not use tight fitting clothes. You do not want to hinder circulation. But you do want to trap as much air as possible. Tight garments can't do that.
The mukluks and anorak I mention have taken me comfortably down into -40F in northern Minnesota and Montana, and they are staples of my gear here in the Adirondacks. Where it usually remains in the balmy -20 to -30 range. And as an added bonus they are both made in the U.S.A. in Minnesota. Can't recommend them enough.
Winter camping is always an experiment. Every time is different. Some days you feel great, some days not so much. Staying hydrated is key. It seems counter productive because of having to pee in the middle of the night. But it will keep you much warmer in the long run. In cold weather, your body need blodd to flow.mand that happens much more readily if you are hydrated.
Get up and pee as you as you are thinking you need to go. The longer you wait, the worse it gets.
As noted above, test fire this stuff in the yard or close to home until you get it dialed in. Make sure your daughter has at least as good of gear as you do, if not better. If she is into this stuff, do your best to keep her into it.
Debrief when you get home.
Where was she cold,
When did she get cold,
How long was she cold before she acted on it.
Women have different bodies than men. They are more susceptible to many things because of that. They have so much more going on. Factor that in.