Breccan came to mind straight away. Would you prefer to avoid another n ending? I think Beckett and Audrey go really well with brother Lincoln. Here are some other ideas:
Ellis
Elliot
Baxter
Bixby
Bridger
Ledger
Jasper
As you like Audrey and Elle, you may like this thread for ideas: Little black dress names! Some from the thread that I think pair well with Linc are ~
Pearl
Elise
Violet
Eleanor
Margot
Kate
Alice