You can't add transitions to your slideshows within DVD-A. You could assemble a slideshow in VV with transitions and create a mpg file and use that instead (with chapter marks at each new pic).

DVD-A does not support adding sequential audio tracks, nor multiple audio streams. You can get an idea of how long your slide show is and create an audio track to match in VV with sequential audio tracks end to end and render it out to ac3 and then associate that file with your slideshow.

Jim