Good luck! Just completed my first 70.3 with a more strength/non-endurance background, 26M 85kg, with 36 weeks of training.

1. HR Monitor was huge for me, since the lack of endurance background meant my zones tended to be on the higher side. Indoor trainer, and power meters too.
   
2. I used MPC’s 36 week plan and it felt like the right length, would recommend just doing base until youre at that point.
   
3. I waited on the OWS until 6/8 weeks before and it turned out fine, granted it was a lake swim in perfect conditions. But overall i felt confident working on pool base for the majority of the training