Yes, though he would have to suckle several times a day for several weeks before lactation would being. If you desire to avoid lactation then only have breast play once or twice a day and skip a day...
no it won't , although some time it leaks a little
If she's lactating, yes.
sure we did it when my baby couldn`t and I needed to keep my suplly up
Yes. Make sure he saves some for the baby.