If the OP is looking for the covers of a specific shoe, I'd start with that manufacturer and see if they offer covers.

To the OP, the cover is just that, it doesn't offer any support for the shoe, mostly just a preventative for stopping mud and dirt from getting into the cleat. With a cover or without a cover, you should be able to use them with platform pedals...or any other shoe you own could most likely be used with platform pedals.