I Think big baby showers are great. I had girls only at mine but had about 40 people. I have been to quite a few baby showers that are unisex bbq's etc and they are really nice! A really great way to involve your partner. I would say with regards to inviting partners I would probably say yes, if you invite some of your close friend couples and then invite a friend and not their partner you don't want them to get upset that their partner wasn't invited or for them to feel awkward not having them there with everyone else in couples..... I know it sounds petty but it's surprising how some people get offended by the simplest things and being pregnant you don't want to or shouldn't have to deal with that kind of crap! Hope it all goes well and you have a beautiful baby shower/BBQ!! Xxx