G'day from way down under!

I have someone driving for 2 hours on Christmas day.  Not a mobile phone user, does not want one!

Thought is from a relative, that if we can give her an active phone for a day or so, and have it turned on, with the driver, she could be tracked on the journey.

So - a couple of questions to my NAT friends :-

1. Do trackers work across systems?  Can an android phone find an I-phone, and/or vice versa?  [ my logic says that should not be any problem.

2. Does the 'tracked' phone need to have whatever "App" as well as the phone doing the tracking?

Thanks in advance - just we do not have much time to sort this out - currently 10.00 pm Sat evening!