Three of the attendants have his tracking mark on them. Plus the one on Slav, the one on Monarch Life's Worth, and the one on Monarch Forced Exchange, this made a total of six of his tracking marks. This is every tracking mark that he can use at this point.
He gained an extra tracking mark when he advanced to rank 6, and it seems the tracking marks are capable of so much more than telling him the direction of prey. So his Tracking Ability can be said to have undergone both quantitative and qualitative improvements ever since he became a divine being.
After killing them, the sect sent a bill for the lives of the ten people. He ate the bodies of the four bystanders and the three attendants without his tracking mark on them.
He ate them by covering their corpses with the black force field. The black force field grabbed them, shrunk them, and took them back into his Cave Heaven.
