No, you do not need to keep your cats away. There are no warnings about this for Advantage Multi (Advocate)

Hi According to manufacturer (Bayer) it is ok to use for dogs. This is from their product information page: "Studies have been performed to determine the safety of Advocate when administered to ivermectin-sensitive collies. Ivermectin-sensitive collies were treated with up to five times the recommended dose for three consecutive treatments at 28-day intervals. There were no clinical abnormalities or adverse reactions observed in any of the dogs. Work carried out to determine the safety of accidental oral uptake of Advocate in ivermectin-sensitive breeds of dog revealed that 10% of the unit dose given orally resulted in no adverse effects, while 40% resulted in severe neurological signs."

Each packet only comes as a 3 or 6 pack/doses. This is how the manufacturer provides them in the packets.