stroller could be a lot of grass with the bunny sitting snuggly in the grass. For the grass you could get a bunch of green material and just put around the stroller, or if you could find some of that artificial grass or that grass looking indoor/outdoor carpet and put around the bottom of the stroller, and then get some blue material and put over the top, with some cotton-balls glued to it for clouds in the sky.
Turn the stroller into a top hat, and then you and your hubby could go as the magician and their assistant. I will let you guys figure out which is which. LOL
Just some suggestions, they may spark our own ideas. Remember when brainstorming new ideas, that noting should be off limits. Write everything down, you never know when some strange idea that you wrote down may spark a brilliant idea.
you could get some of those fake fruits and vegetables and attach to the stroller and you could have a bunny in the garden.
you could leave the stroller as is and you and your hubby could dress up as ma & pa rabbit taking Jr for a stroll. Or better yet, dress up as Rabbits strolling in an easter parade. Put some lase or other fringe on the stroller to dress it up for the parade.