S&T wouldn't be necessary to make it happen, but LA can't offer full max, if I'm not mistaken, without Bird Rights, which they can only get in sign and trade. And I think the absolute max is what Bron will/should demand at this point in his career. But like I said, the allure of stealing one more ring might be worth leaving a little money on the table and signing outright, rather than going for s&t.
I agree with you about SA though. They prob take both Kuzma and Ingram, maybe also a couple picks. But I don't think Bron will want to leave any money on the table, which is the complicating factor imo. But Bron might end up just signing outright, no sign and trade, to a one year deal. I think if he does that and were to stay with the Lakers after the yr is up, the Lakers would have his Bird Rights and could max him then.