The use of Salo really didn't catch on in North America after the large scale immigration of Ukrainians like some food like varynyky did. Pigs were one of the only animals on a farm you could freely eat (cows were needed for milk, chickens for eggs) so there was a cultural expectation to use every part of the meat. Salo is basically pure fat, even more so than bacon, so while it was very good for those on farmsteads to gain calories to make it through a work day, when that type of work became less common Salo faded out of popularity in North America but still remains culturally available in most Eastern European countries. It's just seen as so "unhealthy" to North Americans that it's usually only sold in specialty shops or by request at a butchers.
Salo as an answer is not accepted here, but there is another question elsewhere in the course where it is. I will try to go over and find it again. Salo is known in English and probably should be accepted.
I've lived in the U.S. almost my whole life and have never heard of the word "fatback." Сало is a Ukrainian, Russian, etc., food, so it should just be called "salo" in English. Chow mein is still "chow mein" in English even though it's a Chinese food. "Lard" is a disgusting and inaccurate translation for salo, and ❤❤❤ is "fatback," anyway??
Yes, the genitive case is used “with the prepositions без, біля, близько, від, для, до, з (in its meaning ‘from’), крім, після, etc.” See http://www.ukrainianlanguage.org.uk/read/unit07/page7-3.htm.
And yes, the ending changes based on the gender of the word. “Salo” is neuter (the -o ending is a strong clue), so see the table, e.g., here: http://www.ukrainianlanguage.org.uk/read/unit06/page6-6.htm.