The Jumuah Khutba

Imaam standing on the Mimbar after the khutbah and making an announcement for straightening the saffs

Q: 

1. After the Khutbah on Jumu'ah, can the Imaam continue standing on the Mimbar to see that the Masjid is being filled and there are no spaces? 

2. After the Khutbah on Jumu'ah, can the Imaam continue standing on the Mimbar and make the announcement for straightening the Saffs? 

3. What is the ruling regarding waiting after the Khutbah on Jumu'ah to let the Masjid get filled?

Khateeb making a mistake in the khutbah

Q: The Khateeb in our district Masjid in the Arabic sermon - khutbah, he reads it as "fakheemil ithm" instead of "ism". A scholar says that this is totally incorrect as Naoozoobillah you are saying that Allah Ta'ala commits great sins. The Khwateeb was asked to correct it, but doesn't do it. He continues to recite in this manner.

1. Is it true that the meaning actually changes and it can lead to kufr?

2. Should the Khateeb be allowed to continue giving the khutbah if he fails to correct this mistake?