Food wise, I'm easy & happy to go with whatever suits The Host best.
If an opinion's required: I'd def go w the double spit w pork & lamb, w extra from gourmet sausages. A token salad or 2 would b nice, but not essential if it's a hassle. It's a booze-up anyway, so I'll take a break from healthy eating for one arvo. Hell, even just snags & bread would b ok if the rest is too much on the day!
If 2 spits = 20 kg of meat, do we need the snags? It might b worthwhile trying to get some numbers on who's sticking around for how long (eg: I'll b there for most of the arvo but then drive home, so I'll skip the booze-up later in the night - hence I'll b there for one meal maybe).
If The Host reckons he can concoct some serious crackling on piece of spitted pig, I'd even b tempted to vote for 2 pork spits...