yes, the no has to precede the verb and any object pronouns that you decide to put in front of the verb.
So: Yo voy a la casa -> Yo no voy a la casa.
Wrong would be Yo voy no a la casa.
And for the ojbects:
Yo te veo -> Yo no te veo.
Wrong would be: Yo te no veo.
They both may mean "but" however they are used differently based on the sentence structure. Pero is used in the structure "I do this, but not this". Sino can be thought of a "but instead" and is used when the structure is "I don't do this, BUT INSTEAD do this".
Está indicates something temporary. When dealing with colors, you have to use es. If it is something that can change color, then you should be able to use está. In general though, you use 'es' with colors.