In my last batch I added apple vinegar as (or instead of) the starter fluid and it's working really well - actually a lot better than the kombucha that came with the scoby. So apple vinegar doesn't harm the scoby for sure
I've seen an YouTube video where a guy showed kombucha brewed on Yerba Mate. I'm new to brewing (on my 2nd batch) but I will test 100% Yerba Mate in my next batch.