Regarding freshmen big men at Illinois, I looked at points and rebounds for freshmen going back to 1980, and included both Centers and Forwards (excluded those with less than 1.0 ppg) -
1981-82
Anthony Welch, 3.0 ppg, 1.5 rpg
George Montgomery, 3.6 ppg, 3.7 rpg
1982-83
Efrem Winters, 12.4 ppg, 6.9 rpg
Scott Meents, 2.8 ppg, 1.2 rpg
1985-86
Lowell Hamilton 3.7 ppg, 1.7 rpg
Olaf Blab, 1.2 ppg, 0.6 rpg
Jens Kujawa, 2.3 ppg, 2.4 rpg
1988-89
Marcus Liberty, 8.4 ppg, 3.9 rpg
Andy Kaufman, 4.3 ppg, 1.7 rpg
1989-90
Rodney Jones, 7.4 ppg, 4.3 rpg
Andy Kpedi, 2.8 ppg, 2.8 rpg
1990-91
Deon Thomas, 15.1 ppg, 6.8 rpg
Tom Michael, 4.2 ppg, 2.7 rpg
TJ Wheeler, 4.5 ppg, 2.2 rpg
1991-92
Scott Pierce, 5.8 ppg, 3.5 rpg
Robert Bennett, 4.8 ppg, 3.8 ppg
Marc Davidson, 1.7 ppg, 1.2 rpg
1993-94
Jerry Hester, 8.1 ppg, 4.0 rpg
Chris Gandy, 3.4 ppg, 1.9 rpg
1994-95
Jarrod Gee, 6.0 ppg, 3.4 rpg
Brian Notree, 2.6 ppg, 2.1 rpg
Brian Johnson 2.1 ppg, 2.0 rpg
Brett Robisch, 1.3 ppg, 0.7 rpg
1995-96
Ryan Blackwell, 3.9 ppg, 2.9 rpg
1996-97
Victor Chukwudebe, 2.7 ppg, 2.2 rpg
1997-98
Sergio McClain, 3.5 ppg, 3.1 rpg
Awvee Story, 3.2 ppg, 1.9 rpg
1998-99
Lucas Johnson, 4.4 ppg, 3.1 rpg
Damir Krupalija, 4.6 ppg, 5.5 rpg
Robert Archibald, 3.0 ppg, 3.1 rpg
1999-2000
Brian Cook, 9.0 ppg, 4.5 rpg
2001-02
Nick Smith, 3.8 ppg, 2.2 rpg
Roger Powell, 2.9 ppg, 1.8 rpg
2002-03
James Augustine, 7.0 ppg, 5.8 rpg
Kyle Wilson, 2.6 ppg, 1.6 rpg
Aaron Spears, 3.2 ppg, 1.5 rpg
2003-04
Brian Randle, 2.7 ppg, 2.3 rpg
Warren Carter, 1.2 ppg, 0.6 rpg
2004-05
Shaun Pruitt 1.4 pff, 0.9 rpg
2005-06
Richard Semrau, 3.6 ppg, 2.2 rpg
Brian Carlwell, 1.7 ppg, 1.4 rpg
Charles Jackson, 1.1 ppg, 1.5 rpg
2007-08
Mike Tisdale, 3.6 ppg, 1.7 rpg
Mike Davis, 2.6 ppg, 1.8 rpg
Bill Cole, 2.3 ppg, 1.4 rpg
2009-10
Tyler Griffey, 3.3 ppg, 1.8 rpg
2010-11
Jereme Richmond, 7.6 ppg, 5.0 rpg
Meyers Leonard, 2.1 ppg, 1.2 rpg
2011-12
Myke Henry, 3.2 ppg, 1.1 rpg
Nnanna Egwu, 1.9 ppg, 1.5 rpg
2012-13
Maverick Morgan, 1.5 ppg, 1.2 rpg
Austin Colbert, 1.3 ppg, 0.8 rpg
2014-15
Leron Black, 5.0 ppg, 4.3 rpg
2015-16
Michael Finke, 7.5 ppg, 3.7 rpg
2016-17
Kipper Nichols, 4.9 ppg, 2.9 rpg
2017-18
Greg Eboigbodin, 2.2 ppg, 2.4 rpg
2018-19 (through Rutgers game)
Giorgi Bezhanishvili, 12.2 ppg, 5.0 rpg
Samba Kane, 1.9 ppg, 0.6 rpg
Illinois has never had the reputation for acquiring and developing big men, but suffice it to say that if the season were to end today, Giorgi has had the 3rd best freshman season of any Illini big in the last 30+ years, and the season's not out yet. The other two (Efrem Winters and Deon Thomas) had pretty great careers as Illini, and Giorgi is on the right track. Even lottery pick Meyers Leonard's sophomore season was only a bit better than Giorgi's at 13.6 ppg, 8.2 rpg. (Meyers leaving for the NBA was the right thing for him, but we will always wonder "What if. . . . ?")
I'm not going to go back and dig up the data on freshmen duos, but suffice it to say that Giorgi and Ayo are amongst the top 2 or 3 freshmen duos over the same timeframe.