The chemical warfare thing - it's hard to say. I believe it to be a factor but it's not necessarily "all gloom and doom." Best thing to do is observe the anemones and see how they do over time.
One thing I noticed along the chemical warfare thing was along the lines of multiple BTA's competing with non-clonal BTA's. When I had 2 BTA's (1 of each) in the same tank, no problem. Then one split and it was 2 versus 1, again, no problem. But then one of the splits, split again, and now it was 3 versus 1, and the non-splitter was suddenly not opening up as much. I sold two of the splits, back down to 1 and 1, and the non-splitter opened up again normally. Whether I was just observing random things and interpreting it as a pattern, I can't really say, but I'm more careful to sell off splits nowadays just to be sure.
However, in the "normal" situation for me, I have 2 BTA's (non clones), and 2 gigantea carpets in the same tank. I don't really recommend this because I just don't know if "one day" this will become a problem, but it's been about 3 years like this now, so it's fair to say (I think) that sometimes they can coexist. Again, really sort of hard to predict what can happen, I think the best approach is to observe, and be prepared to do something should the need arise.
So, anyhow, sounds like you might have gigantea. That's really cool, they are definitely my favourite.
Would love to see more photos when you have a chance.
