After playing this formation a few times (3-4), there's a few situations that I've came across where the Haemy loadout has mattered.
Talos: Ichor Injector & Heat Lance
Haemy: WWP, Flesh Gauntlet, Splinter Pistol, Relic
I have fielded the Liquifier gun on the Haemy for Overwatch reasons; however, the S3 is a huge hit and isn't that effective against major hitters who may be assaulting this unit.
As for the Haemy Relic - I tend to lean towards 1 of 2 options depending on the points. The Nightmare Doll is my go to due to the +1 FNP roll but also the ability to negate an Instant Death. First couple times playing the formation, my opponent would send S8+ weapons my way and if I failed my 2+ LOS, he was instantly doubled out.
I also look into the Mask - not because I think the Haemy is capable of winning fights against other melee ICs, but the -5I is huge to make sure my Flesh Gauntlet gets an attempt as well as any wounds carried over by the Talos/Cronos is able to hit it before they get to hit. Carrying over wounds into/out of challenges now makes the Haemy about delaying my opponent's beatstick instead of actually meeting it head on.
Just my take on the formation based on my experiences thus far.