Gender neutral is a nice touch for most nurseries. It gives your children a chance to develope without the need to worry about conforming to gender norms that should not exisit in their world.
Some parents enjoy giving their child a chance to prepare for a sibling by giving them dolls. Yes even little boys. While the boys may be given blue dolls you can give them a blue one to match. Blue cribs are rare when it comes to dolls though. But the solution is simple.
Buy a white one and paint it.
Also for bedding you can measure the crib and go to the fabric store and get relevant "boy" fabric to use as sheets. You can even take him with you so he can pick his favorite print.
If you opt for a fleece or felt, there won't be any fraying, however you can use pinking shears on cotton/flannel to prevent fraying if you can't sew a hem on.