How do I prep a counter formation against this?

[Buffs Mad]

The team probably contains unsigned players. When players are unsigned they stay in the same positions in the squad list but are inelligible to play so don't appear in the preview.

They will be replaced when the match starts.

As Tactician says its probably a 442.

The only way you can check for sure what the formation is if you check his previous fixture.

PS. It would be better if the Engine sorted the Squad list at the start of the day rather than waiting for the Prematch simulation period. No idea why they chose to do it like this unless they know something.....