Hi Biscuits,
First of all, do not make your friend more nervous than what she might be by now. She needs to be fully aware of all potential risks but as well, take with a grain of salt some irrational stories that you can hear.
Second, we will need to understand were she is going. The area that you mentioned (Perú, Ecuador and Chile) is about 2.5 Msq Kilometers, that is twice the size of Alaska. It includes a very diverse geography like parts of the Amazon jungle, the Andean mountains, deserts like Atacama in Chile (the driest in the Americas) and many islands like Eastern and Galapagos, just to mention the most famous. To recommend PSK items we will need a deeper understanding of the environment that she will face.
Laws and culture varies extensively from place to place.
My first advice will be to limit her blades to a small one and as standard as possible (a SAK won’t rise much attention here). Of course if she plans to fly while in there, any knifes will need to be transported in the checked baggage.
On drugs, most of Latin American countries have a very liberal distribution, but it makes sense to declare in customs any medication that she will be caring.
As far as battery operated equipment (flashlights, GPS, etc) pick something that uses very common batteries, I strongly recommend AA. Most of lithiums are almost impossible to obtain in remote areas.
Hope this helps.