do I need to express? you don’t need to - only if you want to. It can be useful to have a stash of milk so you can leave the baby with someone else now and then.
Will it increase my milk supply? (I do have and use electric breast pump) yes - the more milk you remove by feeding or pumping, the more you produce.
do I have less milk for my baby after expressing?
Sort of - you shouldn’t express immediately before a breastfeed or you will remove the milk your baby would otherwise have. Better to express at the end of a feed. Or if your baby only feeds from one side at a feed, express from the other side.
how do I know my baby gets enough milk from the breast?
If your baby is gaining weight and has plenty of wet nappies they are getting enough.
how many millilitres of expressed milk should my partner feed my newborn at night (per one feed)?
Not sure, I’ve never done this.
should I bf only on demand even if she doesn’t wake up for 4 hours?
At two weeks I would wake her for a feed after 4 hours. Once she’s a little older (4/5 weeks) you can leave her to sleep for as long as she wants.
can you drink (small amounts) of alcohol while breastfeeding ?
Yes. You would need to drink a lot of alcohol for it to get into your milk.
is it worth getting expensive, double breast pump (like Medea)?
Very personal decision. If you plan to express a lot it may be worth the investment. A hands free pump really frees you up and gives you more time with your baby.