In my opinion the wide picture window root this house in the 60s. I would make the windows less wide and likely make one deeper too. I would render a crisp white and then add timber cladding to match the garage door- the placement of this cladding is down to personal taste- you could add a window width strip under the far left window which would balance the garage doors. Personally I would like to see a door sized wood cladding section to the left of the front door as I think this would give the door more prominence.

Very marginal for me. I think I'd go with vertical as I find the horizontal boards under the overhang a bit busy, it also goes with the doors and windows but contrasts with the stone. I do however like the horizontal lines next to the door as the door doesn't stand out quite so much to me with the vertical planks :)

Try looking at various Architects websites - a rally good one is https://www.backtofrontexteriordesign.com/

Western Red Cedar is more durable than Siberian Larch. Accoya and Thermowood are also good options. I prefer vertical slats personally, I think it’s easier to install, more weather proof against driving rain and looks less like a shed or fence. What type of cladding pattern are you going for? T&G, Shiplap, Board-on-board… Will you be leaving it to silver or sealing with a finish? Bear in mind you need to create a ventilated rainscreen, vertical cladding will require cross-battens whilst horizontal requires only vertical battens. I would also research into creating fireblocks within the ventilated rainscreen. Check out the Timber Decking & Cladding Association, they were super helpful in advising me in the different methods/materials for cladding my garden room. They have free literature on the topic too if you want to jump down the rabbit hole further :-) https://www.tdca.org.uk/