I'm no expert, but agree about the second plan's dark, central section. This may not be a good location for a study nook. As it would require the lights on any time is used, & who wants to be staring straight at a wall anyway. In saying that, I've heard north facing studies can suffer from glare on computer screen, so you'd want to be careful where you set up computer equipment (if you have a desktop) in the northern living area.

Other thoughts. Your plan consolidates your wet rooms better, keeping them closer together. This minimises plumbing runs, which saves on contruction costs. It also saves on water, as you don't wait so long for hot water to reach the tap.

But in your plan the laundry is a long way from the bedrooms. So you really have to think about how you use the laundry. Are you happy to have it near the kitchen, so you don't forget that the machine has finished it's cycle, & the clothes are ready to be hung out? Or would you prefer to have easier access to the bedrooms, to cart dirty clothes & bedsheets? Or can you plan to have access to both.

Next, your plan has a western kitchen, while your partner's had an eastern kitchen. Some people prefer an eastern kitchen, with an east facing window, to get early morning sunshine.

Without windows drawn on your plan is hard to know what you're planning. Do you plan to only have northern windows in your living area? Or were you planning on having an eastern, or western window, or two? It might be nice to have that secondary window in the kitchen, to aid with ventilation, & removing cooking smells. Though if it's facing west of make sure it's pretty small.

It looks like your eastern aspect will be nicer, your home built further from this boundary, so more room for plantings, to increase privacy.

Overall, I'd prefer your plan. Most windows in the living area facing north. An east facing window in the living room to aid cross-ventilation, but not too large. Maybe a small west facing window in the kitchen to aid with ventilation. But I'd make sure this is shaded externally in the summer.

I'd work on ideas for the bathroom & laundry area. Investigate a million ideas, see what will work best for your family. Laundry access from the kitchen. Laundry access from the hallway. Access from both. Access to the outdoors/no access to the outdoors. European style laundry in the kitchen. European style laundry in the bathroom. The choices are just about endless.

Having the toilet (with its own basin) separate from rest of the bathroom would be a good idea, as it'll be a 3 bed/2 bath home. Nice if all wet rooms have access to a window.

It's a bit of a puzzle to try & get it to all fit correctly.

Lastly, I love that this is a "passive solar" renovation. Orientated correctly. So you'll have beautiful winter sunshine in your home, while keeping the sun out in summer. Are you planning an outdoors area to the north? I'd just be using northern length northern eaves on your living area. So that winter sunshine streams in the home. Horizonal awnings can be used for any outdoor area, or a pergola with deciduous climbers.