Is it legal to Sell and make a profit from a Proton Pack?

No...well, that depends, if you have one that's already made and you want to sell it, that's ok, but if you mass-produce them for the sole purpose of selling them to make a living, that's a different story. The design of the proton pack is the sole property(copyright) of the designer/studio that created the movies, which in this case is Dan Aykroyd/Sony Pictures, if you were to make them to sell as replicas for any profit and got caught, that could constitute design/copyright infingement.