I think William Jesse with the nickname Liam is a great option. You say yourself that you like trendy so Liam fits right into that, however you've given him the choice of a more classic and less trendy name for when he's older. Best of both worlds! Thank you for thinking of your child as more than just a cute baby but someone who will one day be a man :-)
Oh, and I just wanted to point that I think Liam is also an excellent name on an adult. It's very popular right now and a bit trendy, but certainly not a bad name by any stretch. I really like it.