Exposing one's Satr

Q: To what extent do women have to lower their gaze with and towards other women if they do (when there’s no fitnah)? I know that you can’t see from below the navel to the knee and including the knees, back and stomach. 

Now in a normal setting among other women, everyone is fully covered but not always in “modest” clothing since it’s females. So in some areas clothes are tight like when wearing a t-shirt for example or trousers. When they wear clothes like this for example, the shape of their body is shown. Are we sinful if we look at their body? Or if we see the shape of things that are apparent or showing (when there is no fitnah)?

Are we supposed to be lowering our gaze as females to other females too? Because when they move etc. even then things naturally show, so what do we do? Are we sinful if we’ve looked or if we’ve seen anything? 

Q: If a man is wearing shorts and his knee and a portion above his knee is exposed. Can such a person greet? As they are saying the name of Allah while their 'awrah is exposed? 

And what is the ruling regarding saying alhamdulillāh after sneezing when one is dressed in a similar manner? Is it makruh or more serious?

Q: Please give the ruling regarding covering hair at home for women.

Q: Is the shape of the forearms and calves of a woman required to be concealed infront of non mahrams? 

Also, what about the upper half of the forearms and lower half of calves, as the shape might be exposed if the abaya sleeves fall down or the dress goes up due to wearing tight sleeves and leggings (to conceal skin)?

Q: Can a woman ride on the back of a motorcycle? The man drives and the woman rides on the back.

Q: We are baaligh women, and our ears are not pierced yet. Now we wish to have our ears pierced, but we cannot find a single lady to do it for us. In this situation, can we get our ears pierced by a male?

Q: Is my 2.5 year old toddler allowed to see my breast? 

I have a 3 week old baby and my milk supply is low. I have been advised by lactation specialist to let baby suckle as much as possible to increase my supply, minimum is 30 min every 2 hrs. But my toddler only sleeps 1 hour some days. I am alone during the day and nowhere to put my toddler every 2 hrs. 

So my question is, am I allowed to breastfeed my baby in front of my toddler?

Q: I wanted to ask a question regarding the dressing of women in their own homes. In my house we have our own gym area where me, my mother, and sisters exercise. While exercising they usually wear shorts that go till the knees and a low cut tank top that shows their cleavage. Their nipples are sometimes also visible sometimes. Is this allowed Islamically if there is no fear of fitnah?