I dunno. The “Friends” in the second slide look like they might be a bit more than friends.
There are a couple of options there that could fit the pre-married test their relationship category, but they are definitely missing a few of the normal categories.
Both border patrol agents and federal agents should make for an interesting dynamic.
Nah–gay only counts if that’s their only reason for being on the show (“We’re here to prove that gay couples are JUST LIKE any other couples and can compete just as well”).
Ditto with pre-married test ones. Unless that’s the first words out of their mouth or in their description (“We’re a dating couple. I love him but he’s afraid to commit. We’re going to use this race, which isn’t like any other situation we’ll ever find ourselves in to test our troo luv.”) it doesn’t count. 
Theoretically, the Race CAN be a way to test your relationship under stress. The problem is that it’s a test under the Amtal Rule from Dune…a test to destruction. There’s SO MUCH stress and fatigue and you’re together 24/7 for over a month and, basically, if the relationship doesn’t completely self-destruct, you should be able to make a go of just about anything together. But it’s not a “test” in the sense of “Oh, we’ll be together a lot so we’ll see if we’re compatible over the long term.” Being together a lot is fine, but you’re also going to be multilaterally misunderstanding clues in multiple ways, arguing, being completely sleep-deprived and working each other’s last nerve.