Breastfeeding one's baby in front of a toddler

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?

Performing tawaaf with long intervals in between the rounds

Q: Is it permissible to separate tawaf rounds due to pain? 

Example, I did a few rounds of tawaf one day and a few another day until the seven rounds of tawaf have been completed? 

In the above mentioned situation, if a person is unable to do complete seven rounds of tawaf walking in one go due to pain but can do it separately like the above mentioned situation, will it be permissible for him to do complete seven rounds of tawaf in a wheelchair?

Paying interest fees with interest money

Q: Is it permissible to pay interest fees with the interest received, from and to the same party. 

E.g. A bank rewards its client with an interest % for utilising a savings account. On the other hand, the same bank charges the client an interest fee for using its credit card facility. Can the client pay the latter with the interest received? As it will be returning the same interest to the bank.