I have towed boats and campers with a 1999 and 2002 Navigator and 2003 and 2016 Expedition. All towed well, writhing their limits. You don’t mention what year, but 2015 and newer with the ecoboost motor have much better power.
That said, where these vehicles can come up short is payload. My 2016 had a payload if only 1319 lbs. if you have a carload of people or gear, you run out of capacity. Your trailer is fairly light, as is the tongue weight. I would tow with the Navigator, just be aware of its limits.
2018 International Serenity