Aww a Calico! I love those- Growing up we had one, her name was Astra. (As-Tra)
We also had a long haired tabby named Cheetah- They were step sisters

They both lived for 14 years, Astra got really sick, we had to put her down, and cheetah just passed due to liver problems, but I think when Astra went she gave up- They were really close!
That is great your kitties love Oscar- The 2 cats my Mom has now hate Peanut LOL, When we go over there we have to put the gate up

Poor Peanut just wants to play, but the kitties want nothing to do with him