There will be no risk of galvanic corrosion as long as the tank legs are connected in a manner such that the stainless steel and carbon steel are not both in contact with a common electrolyte. Painting the carbon steel legs is a good idea for preventing corrosion and an epoxy coating as you suggest has very good corrosion resistance. I would work with your coating supplier to develop specs for your specific application. As always, surface preparation is very important when applying a coating. In general for carbon steels, a surface preparation of SSPC-SP-6 (Commercial Blast) or better is recommended for epoxy coatings. Again, I would recommend working with your coating supplier to establish the surface preparation required. I removed your references to a specific coating manufacturer as it is generally our practice not to endorse a specific product.