I just went over December. This might be a bit of a controversial opinion but I would recommend staying in North for the entirety of your visit and then do one or two day trips down to the South. I don't need extreme creature comforts or anything but the South is really isolated and small and the bungalows rather basic. I like the ability to take a free bike out for spin and explore the island a bit, experience different snacks at lunch and get the occasional massage etc (all of which are available in the North but to my knowledge not in the South).
I can highly recommend Veke Veke Village in the North. I absolutely loved that place. The bungalows are bright, clean and spacious and some of the closer ones have wifi access (mine did - otherwise they have wifi in the common dining area and dock), a porch and are all a few feet from a protected bay. You can go out and snorkel or swim from the dock and enjoy the nurse sharks and blacktips and little fish. On nice, dry nights, they serve the included dinner (3 courses, no less) outside on the dock and it is run by a lovely Polynesian family who adore their animals Puka, Pousky (the sharpei dog mixes) and cat Noisette (who always comes to visit at dinner but never begs for food). They offer bikes (its a lovely 10-15 minute ride into the main "town") and it is sandwiched between 2 lovely snacks that offer killer food at reasonable (for FP) prices.
I can't recommend Dive Spirit. From what I heard, they have been through a lot of management issues lately. New management in 2020 but the shop seemed in poor shape (along with their gear) and organization - in December they cancelled tons of dives (and continued to book new ones for the following day when they had zero chance of actually providing them). I can HIGHLY recommend Thibault and his shop at O2 divers. They were lovely people, well run shop, great gear and had a nice family vibe. Plus the location is spectacular. As with all the shops, they will come pick you up from wherever your pension is in the morning (and even take you back for lunch if you have afternoon dives). O2 (as with the others) runs day trips down to the South Pass (probably 1 or 2 a week or more in high season).
All of that being said, I did my double dives down in the South Pass with the local guides that work out of Tetamanu Village and they were fantastic. Food was good too. Just don't think I could spend more than a day there - I would feel too claustrophobic.