Welcome to Pettalk. Romeo & Juliet are gorgeous kittens, and I'm glad to hear that you're getting them altered. My vet often does spays and neuters at 8 weeks provided they weigh 2 Lbs or more. Kittens bounce back very fast from the surgery when it's done at an earlier age. Tissues have not had a chance to swell any with first heats, and the chances of mammary tumors etc. are reduced greatly. If you check their teeth, a kitten nearing six months will have adult canine teeth already in.