We recommend keeping your answers concise and to the point. You can answer, “yes, my sister lives in the US.” The idea is to not branch out into a side conversation by providing information that’s not been asked. For example, your answer mentions Redmond, which could lead to a discussion focusing on your sister rather than you. It may eventually lead the Visa Officer to believe you are at a higher risk of staying back and could lead to a visa denial.
If you’re asked where you will stay, answer that you will stay with your sister.
These answers in themselves are OK. They won’t work against you. However, you are likely to draw questions such as how many and to which universities you applied. If they are in and around Redmond/Seattle, be prepared to provide a decisive answer on why you chose to apply to universities in that region.