Why does a five year old get to say what she wears? Why does she get to wear what the older girls wear? Granted bonnets are old fashioned but a kerchief tied under her chin would keep it in place and not be a distraction and much more age appropriate.
I never said it was the older girls, virtually all the other little girls there wear mantillas. It's an assimilation thing, rather than a disobedience thing. I'm willing to accommodate such a request if it inspires a desire to be engaged with the Faith. I'm working with embers here, I'm not blessed with a full hearth like many of you, after all.

They need to be attached with a bobby pin.
That makes sense. It has a comb in it, but I'll grab a bobby pin for next Sunday.
She could wear a black adult sizes mantilla. I sewed mine to a headband. All you have to do, is put the headband on, and it’s fixed firmly and never moves.
I don’t remember a time when we didn’t say the family Rosary. Regarding the mysteries, it is good to have a decent sized picture book where you can turn the pages fro mystery to mystery.
I've found one on
traditionalcatholicpublishing.com that looks like it might be helpful for her, when she's ready. They've got a bunch of books I've been itching to buy for her and her siblings.
For context, I'm halfway through another 54-day novena for the conversion of my wife, and this relent to the will of my daughter is the biggest break I've seen in her over the past 4 years. So I'm taking subtle steps here so not to "spook her" and undo any of the work of those graces, so to speak.