Is there a large korean community in Scarsdale/edgemont

Yes, large enough for the H-mart to come to this area. There are three Korean restaurants, several Korean after schools, and many Korean churches(serving both in English and Korean).
I raised my son in Edgemont. Prior to becoming licensed as a Realtor, I taught mathematics for seven years. Having first-hand knowledge of the Westchester schools, I was involved in local schools as a volunteer translator for Korean ESL students/parents. As a Korean/English speaking bilingual agent, I will be happy to serve Korean American community.

It is best to check with the town of Scarsdale and the churches in the area. As for finding your "dream" home this is my expertise which I can help you with, let me know your criteria and I will help you search.