Tom
I don’t have the competitors manual in front of me so I can’t speak to the profiles you’re looking at but having done the race a couple of times (and again in a few weeks) hopefully I can clear up any confusion.
Once you exit the swim you have a short 3-4 km ride along the waterfront and then there is a short/sharp uphill up the Napier/Taupo higway (probably about 1 km). It then continues to go up and down a bit (mostly up, but nothing steep) for about 15-20 minutes until you reach the high point of the course (by a motor racing track on your left). You continue straigh ahead from there with a gentle but steady downhill for about 15 minutes until you reach the flats. From there its essentially flat out to the Reporoa turn around, broken ocassionally by small ups and downs which are a nice break from the aero position.
On the return journey you do the same up hill to the racing track turn off (a right hand turn). Its nothing very steep but it does go on for a while and on the second lap especially the legs are getting quite tired as its around the 165-170km mark. Once you make the right at the race track it’s mostly a nice little rolling downhill down to the waterfront - good for recovery and stretching the body out a bit, especially after the second lap.
Then around again, along the waterfront up the Napier/Taupo road etc. The only difference on lap two is that when you get to the top of the climb on the way out you turn left instead of going straight on and then go down a bit and turn right on to a private road before joining the main route a bit further along. This is slightly downhill and then a gradual uphill - nothing too difficult. It’s there just to make up the distance.
So to answer your question more directly there are four climbs - one on the way out and one on the way back for each lap, with a little extra thrown in on the second loop out. I’m not sure about others but I generally find the climb back in to town quite a bit harder as it just goes on for quite a while and is often in to a bit of a headwind.
Sorry - I haven’t done Canada or Hawaii (not fast enugh for that :-)…maybe one day) but in terms of nutrition all I can say is that special needs is well placed just after the short, steep climb on the Napier/Taupo road just after you start lap two so it may be good to store extra nutrition here. Here it’s just a gentle uphill rise so it makes it quite easy to take on board extra bottles/solids etc.
The only other two comments I would make are to be wary that the road is quite rough with its coarse chip (I don’t have anything to compare it to but the foreigners I’ve spoken to confirm it is quite hard and “slow”). The other thing is also to make sure you have plenty of warm clothing as while it may be hot out there at that time of day it is often very cold/damp for the first few hours of the bike - this has caught out quite a few people in the past.
All the best for the last few weeks of your training and I look forward to seeing you in Taupo.
If you have any other questions please don’t hesitate to let me know.
Regards
AMG
Just a couple of extra comments after seeing your second post - you couldn’t call Taupo a hilly course. Where the climbs are and given the length of them (not being very long) I would be more focussed on setting my bike up for the flats which make up most of the ride. The climbs can be ridden quite easily and wouldn’t need to be especially geared for (in my opinion at least). Your comments on the headwinds are correct. To my knowledge since the IM has been in Taupo they have never really had strong winds on the bike but it can happen as I’ve trained in some ugly winds out there on more than one occasion. Invariably what seems to happen is that there is usually very little wind early on but as the day goes on it picks up - accordingly affecting the slower cyclists more (a good incentive to train more 
). The descents are fairly easy - straight on the way out and mostly straight on the way back. The only sharp downhill turn is when you come back in to Taupo township and turn left on to the main street. As mentioend above I would prepare for rain - it can pour down here, but it can equally be a scorcher with not a cloud in the sky either. In terms of tires I’m not really a good enough cyclist to comment on what’s best but the good ones I’ve spoken to go wider for that extra bit of cushioning - their comments were that the minimal time difference was worth it for the comfort.
Hope the run was fun! (It’s a nice sunny, warm day here in Auckland with a gently summers breeze blowing )
AMG