Anubias will do fine with the pleco. As far as cultivating it, Anubias is probably the slowest growing aquarium plant there is. You'll be lucky to see more than three or four new leaves a year so it won't be filling out very fast. I've used Anubias in other tanks just never with sunfish.
Gotta love sunfish, I've whapped some monsters. What do you think about hoping a bow fin with sunfish until he out grows the tank? Good to know swear that pleco would eat cash if I put it in there. Anything green is gone before I know it lol.
Typically most plecos won't eat live plants and most fish don't like Anubias anyways because it's leaves are so tough. But my sunfish always seem to tear up plants just for the heck of it.