A ring box is lovely and safer. They look like tiny trunks or treasure chests covered in lace. You can also have the boy walk the flower girl down if she isn't throwing flowers.
Instead of pillows, try a treasure chest--greatly appeals to little boys. Or a treasure box, typically a simple jewelry box with a key--just make sure somebody has the key
There are many different things to use such as just a ring box in the shape of a heart, or a bible with the ring attached to the ribbon, a birds nest, or even a satin drawstring bag would do.