So sorry for you and your kids, and the frizzle who lost her buddy.
Hawks are so bad here and it's against the law to kill them.
When my flocks were young (I have 3) I would have to physically put them into the coop after dark. All 3 sets did the same thing, roosting right in front of the run door. Now they all go inside like clockwork.
Introducing newbies is hard, and who knows if they'll ever co-mingle. If you do decide to try and coop them, maybe just make a separate area for the silkie. Just a poultry wire divider, so she can see the others but they can't pick at her. (?)
Allowing my chickens to free-range is important to me, and I can't be home everyday, although mostly I am. I'm outside alot, lol. I let each group out at different times and it's working so far. I have a mobile pet kennel that I put a hound in and keep in their pasture, he quickly alerts to any danger. I also have 4 guineas that will let you know when a leaf falls. I do think guineas would be very difficult to incorporate into an existing flock. They probably need to be raised together to graze together.
I hope you get everything worked out, and feel better. Life happens, we adjust and keep going.
I'm by no means an expert, this is just how I try to keep my ladies safe.
Take care - Jess