All the buses on Disney property are dispatched from a central location. On average, they run about every 20 minutes, but that can vary greatly throughout the day. I've found that during both my on property stays there was one park bus that we ran into all sorts of problems with. Every time we tried to go to that park from our resort, we ended up waiting forever. At AKL it was DHS, and at CBR it was Epcot.
In general, you won't know when the next bus will be coming until you go to the bus stop and wait for it.
For each of your transfers, especially your ADR at Ohana, you should give yourself around 90 minutes. 20 minutes to wait for the first bus, 10-20 minutes to get to your transfer park, another 20 minutes to wait for your second method of transportation, and 10-20 minutes or so to arrive at your destination resort.
Personally, I wouldn't plan to visit two other resort areas on arrival day, unless I was going to get there fairly early in the day, or my dinner ADR was really late. Even then, I would likely plan on traveling "directly" from the Boardwalk to the Polynesian. You could spend over 4 hours just traveling between hotels, if you head back to AKL in between.