Took about a dozen TAM flights about a year ago. They were fine.
Within S America, the IFE is not seat back. A few screens scattered above the aisle. No sound, so lack of English not relevant.
Travellers Cheques? Not sure they'll be any use. I haven't seen them used anywhere in years.
Not sure how stretched he (or you) will be for money - but at Iguazu a trip up the river to the bottom of the falls is an absolute must. Quite the most amazing natural wonder I've ever seen.