CMC, Aiyuk, Purdy, Kittle, and Deebo played 5 games together. Week 13, 14, 17, 18, DP. I took those 5 games and extrapolated them to 17 for all 5 players. Small sample size, take everything with a grain of salt.
Purdy: 316/465 3804 yards, 34TD, 3INT. (Some rushing but who cares)
CMC: 224/1305/7 + 88/71/635/14 = 22.8PPG, 388 Total (RB1, RB1)
Kittle: 71/58/717/7 = 10PPG, 170 Total (TE9, TE5)
Deebo: 116/75/1016/3 + 54/248/3 = 14.2PPG, 242 Total (WR21, WR13)
Aiyuk: 88/54/887/3 = 9.6PPG, 163 Total (WR55 , WR42)
Because of this disparity, I did 1 more comparison.
Deebo and Kittle played 14 games together.
In those games Kittle averaged:
5/3.7/46/.35 = 10.6PPG
17 game pace of 86/64/794/6 = 181 Fantasy Points.
In the 4 games Deebo was NOT on the field Kittle averaged:
6.5/4.25/69/1.5 = 20PPG
17 game pave of 110/72/1169/25 = 342 Fantasy Points.
Obviously, this is only a 4 game sample and it's EXTREMELY weighted by TDs... but the targets, catches, and yards are all significantly different as well.
Not sure if there's anything of substance given the sample sizes available to us, but... that's what's available to us.
Purdy threw 13 TD passes. 7 of them went to Kittle, but 6 of those 7 occured when Deebo was not playing.
Obviously, huge grain of salt given the sample size.