my ancestor: Du Shenyan, Du Fu's grandfather, was a famous poet in the period of Wu Zetian.
Guan Gu: Guan Gu.
in the same year, Lord's favor: it means that all the people in Luqiu were appointed by the imperial court in the same year as Du Shenyan.
So the meaning of these two poems is: My ancestor's literary talent is unparalleled in the world, and he was valued by the court in the same year as your ancestor.