Home captain Euan Spark had injured himself while committing a foul, for which he was booked, and Bright, 18, came on as the skipper's replacement.
And, within minutes, the teenager thundered the hosts in front with a low shot that smacked off the inside of the post and past Craig Gordon.
An equally impressive strike from Hearts got them back level as Dhanda scored his first goal on home soil for the club, cutting inside on the left and sending the ball beyond the diving Wilson.
After setting up the goal that put Hearts in front, January loan signing Kabunga did ever so well to get himself on the scoresheet when he picked up a loose ball bobbling in the box and slotted home.
And he doubled his tally with 10 minutes to play when he was set up unselfishly by youngster Wilson to calmly finish into the bottom right corner with the aid of a deflection.