Ozzy the kombucha should be 'raw' (not pasteurized) and if so it's got live cultures in it. I've never inoculated a pepper ferment with Kombucha but do not see why it cannot be done. I'd make sure my salt was around 3.6% to be on the safer side though. Bottom line I can't see why it would hurt you or the mash.
GreenGuru the starters do indeed impart a taste to the ferment imo. Personally I think whey and sourdough hooch impart a bit more tang in the finished product, but I don't really detect much taste change from kim chi or sauerkraut juice. Any of them can be good or bad depending on your own tastes. I can't tell you what to 'stay away from' mostly because it's purely personal preference. I blundered about and ruined a few first batches, then I used Caldwell's vegetable starter culture and now I pretty much just use salt for most of my stuff.
I encourage anyone starting out to read the fermentation thread and seek out content from Rocketman and Chilimonsta - all three of which were great resources for me when I was just starting. Good luck and post pics!