1)
Here it says "va'Techal". Why does it say about [completing the work for the Beis ha'Mikdash] "va'Tishlam" (Melachim 1:7:51)?
1.
Riva citing R"M of Kutzi: The Mishkan was finished (erected) in Nisan. Tishrei was complaining that nothing was done in it. Hashem promised it that the work of the Mikdash will be completed in Tishrei. Va'Tishlam - Hashem's vow was fulfilled.