tip: arthur merlin words>1000 sort:hits
I see. Are the Al Ghul sisters going to appear? Given your Nyssa/Laurel story being non Siren Laurel it might be a good switch round.
Nyssa, almost definitely, given that she's been a recurring character years and have significant impact on the lives of both Lance sisters. But Talia? She was seriously underused in Arrow, and that was for only one season. The writers were likely not allowed to do more with her, but as a result I'm not keen to include in this, or anything really.