Pardon the language… poor Snape<-- NOPE! THAT CANNOT BE TRUE. LILY FORGIVES SEVERUS. IM ABSOLUTELY SURE! OMG NOPE<-- PLUS Alice and Frank Longbottom are not dead, they're simply at the mental hospital, due to lose of memory after severe torching. Muggles.
YES! Sirius would be Harry's primary caregiver, but Remus would frequently visit to make sure Sirius was feeding him and not being too bad of an influence. Remus: "Why did you teach him that word?! Why couldn't you teach him please, or thank you?!