Lightning breech plug wrench
A Traditions Lightning breech plug wrench is available from Deer Creek Products 765-525-6181 (they do not have a web site or email address) for $13. It's item no. A1519 in the 2007 catalog.
I did a product search at Midway USA, Brownell's, Dixie Gun Works and Cabela's for the term, "breech plug wrench" without success, so Deer Creek is the only one I know of that has it via mail order. I have seen them hanging on the wall in a Traditions blister pack at various gun shops in this area.
The issue with the bore is corrosion, so I think you need a rust remover first. Ballistrol comes to mind, but there are many others. I've had good results with Blue Wonder Rust Remover. A regular black powder solvent is meant to clean out bp fouling and provide some rust protection in doing so, but it is not a rust remover per se. Once you have the corrosion cleaned out, then a bp solvent would be a good idea to clean out any fouling that the rust solvent did not remove (although there should be very little of that left, if any).
Iosso Bore Cleaning Solvent and Polishing Compound would be an excellent choice for the final step polishing of the bore once the cleaning is completed. That is, if the pitting is minor. It won't do the major lapping job that a valve grinding compound would (without lots of elbow grease).