Sorry for the delay, but I'm finally getting back to this.
I never use the media browser, so I had to spend some time with it.
You're right. a lot of those loops are pretty generic, and I'm not really sure where they are coming from.
Use the Program files included with Session Drummer. I think you'll like them a lot better.
When you insert SD2 into your project, select the following options:
MIDI Source Track
First Synth Audio Output ( you can select All Synth Audio Outs later, but keep it simple for now).
Synth Properties Page. This is the SD2 GUI, and you'll need it to access the program files and control your drums.
Each group of 8 patterns include variations on the basic theme, plus a few fills.
Click and drag on the note icon to pull a selected pattern to your MIDI track.
You can build a fairly interesting track this way. The MIDI track can be edited further in the PRV.
I need to clarify this a bit:
"Project has several audio tracks (both instrumental & vocal). Didn't know that track BPM could differ from project BPM but hadn't messed with it and haven't seen that problem before."
You can't specify different BPM for the tracks. However, audio tracks don't necessarily follow the project BPM.
A MIDI track will explicitly follow project BPM.
If your project is set to 120 BPM, that is what the MIDI track will play.
If your audio track happens to be 110 BPM, it will make the drums sound decidedly asynchronous.
It's best to do the drums first, or at least have a click track set to the project when recording your audio.
It is much easier to sing/ play along with the project clock than it is to try to sync the project to an audio track.
As to the dropouts and irregular performance, that is most likely the Realtek. It is fine for basic playback, but does not handle the more complex demands that DAWs put on it very well.
A decent interface can be had for $200-300, and will be the most significant investment you can make for your studio. It will make a huge difference.
Hope that helps.