If you decide on resettling I would try a gentle approach.
So I would stay in his room, either speaking to him but no eye contact or no speaking but having your hand on him. I would make sure he sees you so he doesn't feel abandoned. I would also try to resettle him once not more. So if you finally succeed, when he wakes take him up. I would try to push him for one nap then so let's presume scenario like that:
- 4:00 am WU
- 6:00 managed to resettle for 45min (if he sleeps longer, don't let him go past 7am?)
- 6:45am WU
- nap at 12:00
- BT at 7pm
Be prepared that first 2-3 days could be a nightmare, so try to start when you are ready & steady to go, no as quick as possible.