Concerning Kriat Shema, Arvit, and a combination of both please answer the following:
1. Kindly explain when is the latest time one can recite Arvit and the reason for the answer.
2. Until what time at night can one say Kriyat Shema in Arvit? Why?
3. Is there any restriction as to using Hashem's name in the brachot before Kriyat Shema if one is reciting the shema outside of its precribed time at night?