At least four meatshields are needed to get in the way of the Iron Claw's single target attacks. Use Dragon Cat, Crazed Dragon, Drama Cats, Paris, and any other long-range attackers you have to chip away at the Iron Claw's health. An anti-black unit or two can be used take out the Doge Darks for easy money.
Strategy 2 by DonDonBeo: 8 meatshields and 2 long-range attackers
Line up : Li'l Macho Cat, Crazed Macho Cat, Mohawk Cat, Wall Cat, Crazed Wall Cat, Ramen Cat, Jiangshi Cat, Jamiera Cat, and 2 long-range attackers: Ururun Cat, The Peach Devils (recommend main attackers >410 range to out-range the Iron Claw).
Power-Ups: Rich Cat and Cat CPU.
At first , turn off the Cat CPU , spam Ramen Cat and some Wall to block and kill the Doge Darks. When you have enough money and The Iron Claws is near your base ( don't let them touch your base ) , turn on the Cat CPU and just see what 8 meatshields can do .