DS has had three bottles of formula mixed with breastmilk since yesterday and all is well, so far! Right now I am using the premixed similac alimentum but it will be "bad" by tomorrow so I picked up some powder. I have a few questions!

1. Is it okay to mix with tap?
2. should I just mix the formula/water in a bottle then pour my milk on top (while we continue to mix?)
3. If I don't heat his bottles (he takes them cool) is it okay to re offer after the 1 hr window has passed? We are used to the "room temp for 6 hrs" breastmilk rule so this will be a bit of a change! He typically finishes his bottle at once but every now and then he just snacks!

I'm sure I will have more! TIA!