1) I used Pigeon storage milk bags but i find the price quite steep.
2) According to the lactation consultant at Kandang Kerbau Hospital, you can store ebm at room temperature for up to 4hrs, but if baby's saliva has touched the ebm, it can only last for 1hr, counting from the time the saliva contaminated the milk. EBM can be kept in the fridge for 48hrs and in the normal freezer for up to 3 months. Avoid keeping the milk at the fridge door to prevent temp changes and if possible keep it at the deep end of the fridge/freezer. Ebm can be kept in a chest freezer for a much longer time (6months and even longer). Frozen breast milk can be thawed by placing it in the fridge the nite before or directly in a bottle warmer (will take about 20min or so to thaw and heat up to 40degC).
3) The Pigeon sterilizer i was using can keep bottles sterilized for up to 6hrs. So technically you can sterilize the bottles there and if not opened, they are considered 'clean' for up to 6hrs. I usually sterilize the bottles after washing and after the sterilizing is done, i just leave it alone till the next feed so that i wldn't need to sterilize again just before use (sometimes baby can't wait!)
4) I'm not sure why you wanna start bottlefeeding but if you really need or want to do so, get someone else to do the feeding via bottle. Sometimes baby may reject the bottle if fed by mummy or even if baby senses mummy's presence. The baby may also start rejecting the nipple if she gets used to the flow of the bottle.
5) You dont need many bottles in my opinion. i only used like 2 bottles coz i only expressed milk for dear daughter in the first month or so and there after i latched her all the way till now.
6) I used to pump for every feed and kept the extra (which she refused to drink in the end). It really depends on your future plans. If you're intending to build up a supply of ebm, then you shld pump extra to store. If you just want supply to match demand, then pump just enuff for each feed and maybe a little extra just in case.