Can my daughter also use Lightroom on he mobile device? My LR is synced to windows and 1 iOS phone

Yes. There is no limit to the number of mobile devices that can be logged into the same Lightroom account. You can both use the same account at the same time with your iOS devices. If you use the Lightoom app on a computer you are limited to two computer logins.

https://apps.apple.com/us/app/lightroom-photo-video-editor/id878783582

Here's what it says on the App store: 
"Adobe Photoshop Lightroom is a free, powerful photo & video editor and camera app that empowers you to capture and edit stunning images."

So the answer regarding using LR on the iPhone or iPad is YES.  

You can also download Lightroom via the Creative Cloud onto multiple computers, but only one instance can be open at one time, so you and your daughter would never be able to use it simultaneously.