I disagree with Atticus on hypothetical 2. I reckon consent / court orders trump a signed parenting plan. The only thing that makes court orders obsolete is if a new set of court/consent orders is stamped by the court, or the kid turns 18.
Sammy, did you see the link Atticus posted? It is the Family Law Act itself, and specifically mentions that if there is a parenting plan that is formalised after the consent/court order, then the court must have regard for it and consider whether to vary the order to include provisions in the parenting plan. That sounds very much like it does trump it, or at least
can trump it, at the judge's discretion.
In my case, as I haven't signed any formal parenting plan with my ex, the only thing I have is a very informal temporary agreement to make a minor change to the times and as I said previously, it sounds like the court order is very much still valid despite that agreement.