I'd get a couple more of the closer to nature bottles to fit the pump, saves you washing constantly if you want to chill or freeze the EBM. Hopefully your bub takes to those bottles without a fuss, those ones where the only brand my little one would take after months and months of refusing a bottle. They seem to be a good choice for a BF baby. Perhaps buy one other bottle of a different brand as a just in case but it really just it trial and error if they start refusing. With us the only thing that worked was leaving it for a few months then trying again.