Could relocate kitchen all together to new family room as at the moment there is a small family room close by which is essentially a circulation zone only. the front living would then be much bigger. The little family room could then reworked for a pantry to the kitchen with a linen onto the bedroom side. Relocating kitchen I'd say is a priority though!

Ours never leaked. We'd installed it, then lived in the house 7yr. The previous skylight was leaking badly when we bought the house, it was one of those plastic dome ones- revolting. It was pretty easy to work out why the flashing had corroded in the old skylight- it was chock full of leaf compost. After that- every year the husband would get up and clean the roof gutters and the gutter of the skylight. Like anything regular maintenance will prevent leaks. I'm not sure what the rules are with cyclone-zones. Velux are made from toughened glass. I'm sure their website would give you this detail. Yeah- they get dirty, then it rains and they are clean again! At one stage we got a little bit of lichen growing, but then in Summer it died and just went away! The dirt/dust never bothered us....it's not like you walk around staring up all the time. It doesn't lessen the impact of the extra light and height.

roof without leaks is number 1 priority and although we loved our old Velux roof windows they leaked over time and were too hot on hot days and the blinds are very expensive so they were replaced with Solar Skylights and, although not as pretty as the roof windows and having no ventilation they can't leak because there's no hole in the roof and operate as a solar powered "light" connected to a small roof mounted solar panel with fibre optic cable (our two 25cm Solar Skylights do a great job brightening our 5 x 7 m kitchen dining area and cost about $500 with DIY installation..

Shifting the laundry will create a larger laundry and allow for a 'kids bedroom zone' with better access to bathroom for all 3 minor bedrooms. Place the rumpus where dinning is. This can be separated or use the great sliding wall/door idea. It also allows view from kitchen. I agree with moving the fridge and creating a more open WIP. This also allows for a WI Linen - which could be opened up to the mud room, or even a powder room. I found the front living room to be an awkward size and shape so did a slight rearrange in that area. This gives the Living Room access to the north facing patio/outdoor area, tying all the living spaces together while keeping them seperate.