Yes, Barisone was (is?) one of the partners or owners of the LLC, but as one of the lawyers pointed out, the other owners can sue another partner, either in his role as the trainer using the farm, or in his role as a partner of the LLC, if the other owners think he did something to damage the LLC.
If the only claims in the civil suit were Kanarek vs Barisone and Kanarek vs SGF, I can see the logic of the civil attorneys of the two defendants collaborating.
But I think there is a cross claim of SGF against Barisone. In nontechnical terms, SGF can say “We, SWG, think you made us look bad by shooting a client on our property. The liability should be on Barisone, not us”. In that claim, SGF vs Barisone, the two groups of attorneys are adversaries.
To the extent that Kanarek and SGF are both suing Barisone and saying the sole liability is his, the SGF lawyers and Kanarek’s lawyers are aligned, despite the fact that Barisone is a part owner of the LLC.