���I don't recall any specific epoxy vs stainless reaction, at least for 18-8 stainlesses which are most SS marine fasteners. Now, stainless does have an issue with oxygen starved environments in salt water. Chloride corrosion happens faster with no oxygen to keep the surface passivation layer intact. That can happen with embedded screws, but unless the boat is living in the water, I say it's very low concern. More of an issue on big boats living in salt water. Bronze keel bolts are often preferred due to that, just harder to get sourced nowadays. On my skerry, I bedded the screws with 3M 4200. Mostly so I can get them out easier if I have to.

Yes, Mummichog is correct.  Stainless is fine for your application, where it's not totally encapsulated.  That's why we use silicon bronze screws for the skeg and skids, because they're buried under several coats of epoxy.

If stainless reacted with epoxy, we'd have millions of boats in dire distress.  Oh, wait.  Thanks to Irma & Maria, we do...