  We present photometric and spectroscopic follow-up observations of
short-period variables discovered in the OmegaWhite survey: a wide-field
high-cadence g-band synoptic survey targeting the Galactic Plane. We have used
fast photometry on the SAAO 1.0-m and 1.9-m telescopes to obtain light curves
of 27 variables, and use these results to validate the period and amplitude
estimates from the OmegaWhite processing pipeline. Furthermore, 57 sources (44
unique, 13 also with new light curves) were selected for spectroscopic
follow-up using either the SAAO 1.9-m telescope or the Southern African Large
Telescope. We find many of these variables have spectra which are consistent
with being delta Scuti type pulsating stars. At higher amplitudes, we detect
four possible pulsating white dwarf/subdwarf sources and an eclipsing
cataclysmic variable. Due to their rarity, these targets are ideal candidates
for detailed follow-up studies. From spectroscopy, we confirm the symbiotic
binary star nature of two variables identified as such in the SIMBAD database.
We also report what could possibly be the first detection of the `Bump Cepheid'
phenomena in a delta Scuti star, with OW J175848.21-271653.7 showing a
pronounced 22% amplitude dip lasting 3 minutes during each pulsational cycle
peak. However, the precise nature of this target is still uncertain as it
exhibits the spectral features of a B-type star.
