Using ROS in a Unity application running on iOS?

Hey,

I'm working on an iOS AR application in Unity. Our challenge right now is to localize an iPad within a known space (without using markers like QR codes). Our plan was to use the iPad's LiDAR scanner (and movement sensors) and run the data through adaptive Monte Carlo localization (AMCL). So we've needed to find an implementation of AMCL that works in 3D, and the only options I can find run through ROS.

I'm not excited to work with ROS. We only need it for the AMCL functionality, and it seems like it would invite a lot of problems and bloat. So I've got a few questions:

1. Is this setup even possible? Is this a really bad idea?

2. The Unity-ROS integration package seems to suggest that the two tools work by running separately and communicating via TCP. If ROS can't run on iOS, does this mean we need to have ROS running on a separate machine?

3. How difficult would it be to take the AMCL 3D package and fiddle with it so that it runs outside of the ROS environment?

4. If anyone has a 3D AMCL implementation which doesn't require ROS, that would be great haha