Yes, if you are ill or have a valid excuse then you can pray sitting down, although if you can, you should pray standing up as that is the best.
if a pregnent women is having problem in offering namaaz she can offer namaaz while sitting if she cant even sit she can lay down and offer namaaz and sajdah
yes what is important in namaz is that in wudu water reach surface of your skin and also keep your make up covered from others while namaz.
The prophet himself led the namaz while the companion Bilal (R) was the one who said the adhaan
People recite at a play in English, while they play at a recital in music or dance performances.
It depends what you are sitting on or in.
No, it is not mandatory to recite "A'oodhu billahi minash shaitanir rajeem" (I seek refuge in Allah from the accursed Satan) silently in Salah (prayer). It is recommended to say it silently with the heart and not necessarily aloud like the other portions of the prayer.
Standing
Think.
When sitting on the toilet. While stand with one leg up on a bed or bathtub.
In a chair.
There is many ways to work out while working, if you work at a desk you can try standing instead of sitting, try doing some squats while standing, walk around, take a break and jog in place, leg raises while sitting, buttox sqeezes while sitting.
Aaron likes the KKK