That is so kind of you to raise the two kittiens. They lived a better life for it too, even if they were a bit aloof and standoffish. Of course when aren't some cats aloof and standoffish.....(mine are at times - especially our only girl wo we raised since she was a 3.5 month kitten (also a stray.)
It was very strange. Smudge and Brutus while siblings, Brutus didn't like Smudge. If she tried to snuggle in for a nap, he'd get up and leave. When she developed end stage cancer and eventually passed, he died three months later. Broken heart the vet said. Bella is our first cat since then.