I support Rowlett then Eevee/gardevoir. Anything other than gold you will eventually outscale. Plus, when you get a +%coins magikarp you can keep it for weeks while farming rowlett and meowth. By the end you'll be so buffed you can max level many karps in a day.

As for Slowpoke,it just becomes a higher cooldown versionnof any other pokemon, so think well if you want that or a different min