Based on my chart I established above...:
Samurott covers Zebstrika, Darmanitan, and Archeops' weaknesses to Ground and Rock respectively.
Zebstrika covers Meinshao, Krookodile, Darmanitan, and Archeops' weaknesses to Flying and Water respectively.
Meinshao covers Krookodile, Darmanitan, Haxorus(!), and Archeops' weaknesses to Ice, Rock, Dark, and Steel respectively.
Krookodile covers Samurott, Meinshao, Darmanitan, and Archeops' weaknesses to Electric, Psychic, Rock, Dark, and Steel respectively.
Darmanitan covers Samurott, Krookodile, Haxorus(!), and Archeops' weaknesses to Grass, Ice, Fighting, Bug, and Steel respectively.
Haxorus only covers its own weakness to itself.
Archeops covers Samurott, Krookodile, Meinshao, Haxorus(!), and its own weaknesses to Grass, Ice, Fighting, Flying, and Bug respectively.
____
So, based on this (coverage by type alone), Haxorus doesn't cover for
anyone but itself.