Hmm. Well, if indeed it was dropsy which is not contagious, I'd say everything you have done is sufficient in order to get it going again. I'm not sure what meds are used for dropsy, so as far as your biological filter, ehhh, it depends on what you used for meds. If it were me, (I dunno if it would make any difference or not) I would just put some new media in the filter. There is enough bacteria on the surfaces of your tank, ornaments, plants etc. to populate the filter's bacteria.
But that's just me. You *may* be perfectly fine just leaving your old stuff in.