Are there any Hydrangeas in the vicinity?

Veination doesn’t look dense enough for C kousa imo.

I'm falling in the Dogwood camp, as well - especially with that terminal/bud characteristic.

I thought Cornus at first, but as floral points out, just not enough veins in those leaves.

tj

Here's some updated pics from a few weeks ago:

See how it compares with gray dogwood (C. /aka Swida racemosa). If by "Arbor Day seedling" you meant the Foundation, it is one they carry.