Plumbing in a garage attached to house

Yes, shouldn’t be too difficult especially if there’s a kitchen or bathroom close to the garage wall where you can pick up the hot and cold supply.

Yes, but pipework would need insulating to avoid potential freezing through the winter months

The main concern I would have is the drainage ,anything’s possible with pumps on the market these days but gravity is always the best option when thinking about waste water ,depends on how much ground work is involved,but like I said anything is possible

The previous comments about hot and cold supplies is correct but the pipework would be under the grounnd bit you also require a waste pipe to drain a sink so I would have to connect to the drainage waste but this is possible but would be a bit of a dear price just soyou are aware But I have done a cpl of garage fit outs Mant thanks Sienna plumbing