Splash is definitely associated with blue eyes, but of course, not all will have them. Some none,some one of each and some two blues. We have one Gypsy mare with one dark and one blue. All our others have two dark eyes but I'll bet they all carry Splash.
I'm pretty sure that Shires, like Clydes, all carry some form of Sabino. They were after all, one and the same breed in the past.
The halos around spots are often seen in Appys. Also around edges of Tobiano patterns too.
Funny you should mention raised spots. We were just speaking about this on our Gypsy Horse forum. Many said that the coloured areas were longer haired than the white.