What will be te rise and fall times of DAC, based on Slew rate and settling time
Actually it will "jump" in 4.096/15 or 273 nSec.  Then add the 1 uSec settling time for 1.27 uSec.  

"Glitch Impulse" is caused by variances in the R-2R network switching times for the resistors.  Worst case is the switch from 7FFF to 8000 ("major transition").  Since all of the resistors get switched and they don't switch exactly at once, the output has a little "bump" or "glitch".  It is specified as the absolute value of the area under the curve of voltage (compared to the final value) over the time of the glitch, hence the units are volt-seconds.

"Digital Feedthrough" is the glitch that occurs on the output when the input value bits do not change but one of the other digital inputs (clock, latch, etc) is changed.  It is also specified as volt-seconds.