i think it might be better to have a male and female..i read on a site once that if they aren't in a pair they may be sorta lonesome. however then you will probably have to figure out what to do with the fry eventually.
a paradise fish could be a good idea, they are much more boisterous than a betta (that's the impression i got of them), sometimes even being pretty territorial and aggressive, they would be good with the kribs.
kribs are more acceptable community cichlids than cichlids in general, but they are still snappy little buggers..my gfs tank broke and i let her put her fish in my tank which had two kribs in for about a week, the kribs killed 2 platys and a balloon molly. it seems to have been a territorial issue cause her fish werent smart enough to figure out to stay away from them. you won't have to worry about your tetras (what type are they though?) nipping the kribs..it'd probably be the other way around. your cory's might get picked on..cory's like to be in groups of 6 just so you know.
that being said, I have my two kribs in with a lavendar gourami, swordtail, yoyo loaches. there hasn't been any casualties, but the kribs will chase away the gourami, and sometimes the swordtail (i think it's cause they are of similar size). but these fish haven't been too bothered by them.
your silver dollars need a bigger tank i believe...anyways, someone who knows more about kribs will give more advice i'm new to them, just thought i'd share my experience thus far.
maybe you should check out apistogramma. but cichlids tend to be bottom dwellers, for a centerpiece fish you might want something more in the mid/upper levels.