Safer from Afar does not apply 175% damage increase at 15 meters. Tested by recording my screen and averaging damage based on distance.

Undertaker modifier Hordes vitality does not increase buff duration from 5s to 10s. Tested with a stop watch.

Captured velocity does not apply attack speed or spell speed buffs. Visually don't notice a difference, don't see a buff counter and stat sheet does not reflect an increase in speed