Yes
The earliest round for a 1 seed to go out in the NCAA basketball tourney is in the first round. It happened in 2018 when the University of Maryland - Baltimore County (16th seed in the South) beat the University of Virginia (1st seed in the South) by a score of 74 - 54.
Villanova was an eighth seed in 1985.
No, not yet.
UNC was a number 1 seed in the 2009 NCAA basketball tournament.
1 seed
Wake Forest was a number 4 seed in the 2009 NCAA Basketball Tournament.
The lowest seed to make it to the Sweet 16 in the NCAA basketball tournament this year was a 15th seed.
A 4 seed.
The Kansas Jayhawks
Since the NCAA implemented the 64 seed tournament format in 1985, the lowest seed to make it to the NCAA championship game was #8 seeded Villanova in 1985.
Michigan was a #3 seed when they won the NCAA Men's Basketball Tournament in 1989.
12