My baby is drinking mama milk and Meiji,
he is born on 15/5,
he drinks 3 oz every 3 hours,
sometimes, mama milk + 2.5oz,
so I think your baby is not drinking too much,
and it's good for him to drink so much!!
My first bb and this bb both drink Meiji,
I found it's really good!
yes, you can give bb some water between two meals,
but don't be too much, like 10-20ml (about half oz) each time, my bb now drinks once only each day, but later, he can drink more. I think your bb can drink 2-3 times of water every day.
My bb is drinking Meiji and Mama milk, so his poo poo is yellow in colour, but as I know, dark green poo poo is normal!
I asked the doctor yesterday my bb sometimes has 1-2 poo a day, sometimes has 5 times a day, the doctor said it's ok, so I think keeping having poo poo is ok , if no poo poo in 3 days, need to see the doctor.