We ned to know which ticket type you are trying to use: OneWorld Explorer or Global Explorer? But I'll assume the former. Whether it's "reasonable" is subjective, but will also depend on what class you intend to book in.

1) Nope - no PPT-LAX. That's a non-OW airline operating (Air Tahiti Nui?) so not allowed. xONEn must be OW operated, codeshares not allowed. Similarly SFO-SEA and SEA-MIA are operated by Alaska Airlines, so not valid either.

1bis) If you have confirmed dates in the ticket then you are protected onto a reasonable alternative (even if that alternative causes the rules to be broken, e.g. by going over the segment limit). If no confirmed dates then you need to reroute the ticket (and you might well get hit a rerouting charge to do so).

2) See above for AKL-PPT and the SEA flights. No idea on LAX-SFO; plenty of AA flights there.

3) Yes, provided that the DXB-HKG-PER is a transit at HKG.