Yes, same colour in different textures will provide consistency throughout with just enough variance to make it look interesting. Are you repainting your walls, if so and if you have the time I'd recommend buying sample pots of the whites you're interested in and painting a decent size swatch of them on walls to see their colour change under different lighting- it will look one colour while still wet in the tin, but completely different once dry on a wall under your house lights and the changing daylight. If it's strictly trim you're painting then that's not really necessary. Can't wait to see the end result, the dark beams with lighter trims throughout the house will look absolutely magnificent.

A lighter colour trim is always a good option. If you want to save some money and time jump onto https://www.monstashop.com/ They can send you a free colour deck with all the whites available. Or you can get your Dulux colour matched! All without leaving the house!!

Definitely paint. And an extra tip: We moved into a house with so many boldly coloured walls (turquoise, salmon, yellow, dark blue...!) and ended up finding the Haymes paint was amazing at covering all the colours. In the bathroom we used 2 other brands (Duluxand Taubmans) and they needed manymore coats, I'll only use Haymes now I've tried it. Only needed 2 coats over all the colours, it's not at Bunnings but worth seeking out. We got ours from Paint Spot and the staff were so helpful.

That’s a good idea, we’re going to go with painter on the first room, once he leaves we can decide whether or not we paint the trims. More work, but playing it safe!