Hi! Thank you for reporting this!
I just tried building the ducks and dog set but couldn't see anything wrong with it. There was a problem with the instructions not showing all bricks after loading a save during development but that has been fixed. Do you have a picture of this problem?
Multiplayer is something I expected to become requested but it would require a complete overhaul again and in all the years that I've been working with the Unreal Engine 4, I never touched anything related to multiplayer which would make it even harder to implement. Personally I don't play multiplayer games at all. For now I'm working on actual objectives you can enable when simply building a set isn't as fun.
Thank you for playing!