Hi Sundus,
My wife is also currently 6 months pregnant and we were having the same questions as you are now. She and my son were here on visit visa and their 6 months ended on the 30th of Nov. I managed to speak to the captain at the Gharaffa Immigration and extend for another 2 weeks till 15th of Oct(at the same price though.)

After that i went again to try and extend however they did not allow. But i did get it confirmed from the lady at the immigration that the 3 month ban is no longer active. We left the country on the 15th of Oct, and I came back and applied for the visit visa again (got delayed a few days since I was awaiting for the letter from my office) once I had all the documents ready I went back to the Gharaffa immigration, no questions asked just took the documents and asked to check in 3 days. It took 2 days for the visa to be “ready to print”, they came back again on the 27th of Oct. could have been sooner if I had all the documents ready

So to answer your questions
1- Currently they only extend visit visa till 6 months (previously it used to 1+5+1= 7 months in total)

2- As mentioned on the previous comment i don’t think the type of delivery will affect the extension request

3-Generally doctors don’t recommend "flying" after 7 months. It's best if you speak to your gynecologist regarding any travel plans. Also as per my understanding the moment you leave the country your visa expires.

4-The 3 month ban is no longer valid. Your husband can apply for a new visit visa as soon as you leave the country. You don’t necessarily have to go to your home country, you can just as easily fly to a GCC country (like dubai) and stay there for a few days and then come back once the visa is processed.
Note- If you do plan on leaving the country you need to get a doctor’s note advising that you are ok to travel. This note is valid only for 3 days so you need to take it close to the date that you are flying.