Great middle name, but the association with the singer is really strong for me.
I love it. I think with the popularity of Elliot & Ella & Ellie & -ton names like Ashton, maybe Elton is more of a riff off of that than a connection to the singer. I love Elton John and I do think that like someone like Cher, he is iconic, but not super active within pop-culture. He doesn't court press. I'm sure he will make more music, but I doubt that it would be on the radar of a young Elton's classmates. He might get the occasional comment from people in the mom/grandma age group, but kids won't make that association. Obviously avoid John, Jonathan, Levon, Daniel, ect in the middle...it's too super-fan-ish! It's a very handsome name. Watch Clueless for an alternate association!
No. Just no.