I have Skye Terriers & Cairns along with the Yorkies. I've shown & bred the Skyes & Cairns for over 30 years.
The Skyes are very reserved, extremely faithful to us but wary of strangers.If we get visitors, the yorkies & Cairns are all over them for a fuss, but the Skyes will sit at a distance weighing up whether they'll deign to say hello or not.
I don't agree entirely with Yorkiekist though, all mine have lived very amicably with the Yorkies, the cats that we have & even the geese, ducks & poultry.
i belong to the Skye Terrier Club & we sometimes have weekend meet ups, to which I take my yorkies as well, & they've never been bothered by any of the other Skyes there either.
But I can't keep them in squeaky toys! I have to hide the Yorkies toys from them as they chew up everything apart from the strongest black Kongs!
I can't really say mine are couch potatoes, they're always on the go. They get a really long walk every day & will still run like idiots, playing chase with one another round the garden & fields we have.