Aaaah, I remember the days of the 'kitten collar', my goodness how Harry has grown!!!
Please do have a look (they're nothing to do with me by the way, I just love their stuff!!!) - they do what they call 'teeny weeny' collars in a multitude of designs. And if you don't like those, they'll make them in any combination you wish (including collar buckle colours).
Also, if you email them with your pup's neck size, they'll make them for you personally, at no extra cost, which I think is amazing
As for harnesses, Pets at Home (not online) in their 'puppy' section, I know had really soft velvet ones in pale pink or pale blue, they were gorgeous.
I got Harry's Choke Free imported from the US, it's just soft leather, and I've never had an issue with hair loss or it rubbing him. I think it probably depends on the material that it's made of, too.
A lot on YT use the Buddy Belt, and you can get separate soft liners for that. There's a British website that sells them, I'll have a look and let you know. They're fairly expensive though, so it might be worth getting a cheaper one, until your pup's 'all grown up'!!!
Sally + Harry x