As suspected the smallest one didn't make it past lunchtime, the egg sac appeared to be on the inside and there was a little blood around the 'belly button' area, as well as some skirt damage that could have been caused by the Dad or by Mum traveling over the bogwood as junior was emerging.
By my calculations they are 110 days, so maybe a little premature.
As a first guess I think there's 1 male and 3 females. Two of the females have very symetrical spots.
They're all moving around slowly and breathing normally, so fingers crossed they'll be ok.