Some good advice from Jesse.
29 is a tough size for Malawi cichlids. I have had some success with keeping less aggressive mbuna or smaller peacocks, but they have all been short-term successes. The only setup that may work long term would be a small female-heavy group of salousi. They seem to be the right combination of small and low on aggression.
Afra may work, but aggression/size may become an issue when they get up around 3"
or so. Adult afra can be pretty rough.
As Jesse said,, a 36" long tank would go a long way in greatly expanding your options. Footprint is king for African cichlids. They're all about territory.
If you wanted to do Tangs, you could keep a group of brichardi, leleupi, shell dwellers or small julidochromis. Another option for "short term" would be a young pair of comps and multis. The comps will eventually outgrow the tank, but they grow slow as molasses. If you did this, watch out for aggression from the multis. Comps are armor-plated, so damage wouldn't be significant, but the may end up stressed out.