Yes—your safest path is 70,000 United miles plus taxes.
Your saved balance covers both seats at the published floor.
See the math and another option
2 seats × 35,000 miles = 70,000 United miles
80,000 saved − 70,000 = 10,000 miles left
Typical-value lens: 70,000 miles × 1.35¢ = about $945. Use this only after the floor check.