I havent seen pictures of his dam Wish we could see them. IMO he is pinto but he's minimally marked. And easy way to know would be to pull some mane hair and send them to be tested for Tobiano.
Here is my minimally marked Tobiano that everyone told me I was nuts when I knew he was Tobiano. Pulled hair and yep he's tested Positive for Tobiano. He also carries splash but is LW negative.
And yes shawneen Splash is considered Overo or pinto. As said it could be Sabino causing the leg white but they arent usually that high. I really do feel the spot could be a tobiano marking but wish we could see it closer
I could definitely be wrong on the Tobiano but doubt I am on the splash. The only reason he might not be tobi is because the leg markings arent as jagged as normal Tobi markings
Most do not like to mix pinto and appy genes because it muddies the water and makes it really hard to tell what marking is what. It also makes it very hard to predict what a horse will produce. I myself love pintalossas and have one in the pasture :)
East since there are so many minimally marked Tobianos out there that just have face white and stockings chances are they have registered a lot of minimal pintos :)