I believe UNC will receive the last 1 seed. Though, I do think their resume is comparable to Iowa State's. Committee might dock ISU for having such as weak non-conference, though. UNC's overall schedule is 21st, whereas Iowa State's is 36th. I'd lean towards UNC getting that final 1 seed.
UNC
Q1: 9-3
Q2: 7-4
Q 1/2: 16-7
Q 3/4: 11-0
Record: 27-7
Iowa State
Q1: 10-6
Q2: 6-1
Q 1/2: 16-7
Q 3/4: 11-0
Record: 27-7
The combined Q1/2 record is the same, as is the combined Q 3/4 record. UNC has done better in Q1 games, whereas Iowa State has done better in Q2 games. Iowa State also has 2 wins over Houston.
It'll be interesting to see which 2 seed is aligned with UNC. Often times the committee is wanting to get teams from the West in their proper region, which would mean Arizona. But, If I'm the top 2 seed on the S-Curve, say Tennessee or Iowa State, I'd much rather be in UNC's region than potentially play the likes of UConn, Houston, or Purdue in the Regional Final.