no, twImageInfo contains after the fact details about the images that were acquired – so does twExtImageInfo.
Take a look thru the twain spec in the capability listings, and skim the document Capabilty ordering. Then read the spec cover to cover, then read the spec cover to cover again. The articles toward the end are especially interesting as they cover senerios in a little more detail.
Scanning in black and white or in color is typically controlled by PixelType
For flatbed/feeder capabilites (there are several) search the spec for: ADF(automatic document feeder)
.