Sorry to hear about your experience with the sofa bed. Based on the information provided (4 guests travelling to Sydney with family), the owner made up the master bed and bunk beds for you. They did not realise you were keen on using the sofa bed or that would have set that up (or ensured appropriate instructions).
As to the comfort level, it's subjective - we have had a couple of people sleep on it before, and they’ve been very comfortable. The bed is only 4 months old so you can be rest assured it was still in good shape :)
Bugs - the house is professionally fumigated annually (last time was start of December, 3.5 weeks prior to your stay), but the nature of living in a treetop location close to parks is that there is always a chance of a harmless, yet uninvited house guest. December is peak time for Christmas beetles (they are attracted to light at night), summer is the height of cicada and moth season, and enjoying indoor/outdoor living in the Sydney summertime will always come with some extra friends. Bug spray was also on hand as extra ammunition.
I’m glad this didn’t detract from your stay, that the house lived up to expectations, and that the welcome gifts were enjoyed. The local area has some fantastic eating out and it’s so close to the CBD and I'm happy this was well used by you and your family.
Happy that you found the arrangements we made specially for your Christmas delivery helpful! It was really tricky to engage a team member to specially pick up a delivery during the busiest time of the year but glad it all worked out and was appreciated.