3 foot tank can only handle 1 pair of medium sized cichlids if you went with the kribs you would have more choice for tank mates - if you can find them are a few strains of the pelmachromis family which is the family kribs belong to but the common krib is not as bright as some of its relatives so maybe somthing to look for?
Agreed with above, if you can find Honduran Red Points as an alternative to convicts
or Pelvicachromis subocellatus or Pelvicachromis taeniatus as an alternative to your common krib - Pelvicachromis pulcher.
then you would be able to keep the swords And be able to easily shift the fry if you were to get overun