Just got back from a JFK-SCL-JFK trip on LATAM J. It was on a 787 with the old configuration (2x2x2). I strongly urge you to not select row 1. You'll be constantly bothered by the galley curtain opening and closing, both by the FAs and by pax going to the lavatories.

While the online seat map does not reflect this, there is a massive gap between rows 3 and 4 for the emergency exits. On the return flight, I sat in row 4 and actually really enjoyed the immense sense of spaciousness.

From JFK-SCL, we were given a duvet and pillow, whereas from SCL-JFK we also got a very comfy mattress pad. Service and meals on both flights were great. The menu mentioned snacks in the galley; I didn't want any but didn't see any either so perhaps you have to ask the FA for something extra.

Amenity kit had all the basics and is actually designed for reuse. The lounge at SCL is gorgeous: excellent food spread and showers.