I have had success with Hydrllia and Vallisneria when starting the plants about 2 months before adding cichlids to let the plant roots get totally established.

Other plants did not fare as well, (such as swords and other bulb types) and these cichlids are not Malawi omnivorous cichlids, but are Central Americans, but also not lnown to be plant friendly, its all about choosing non-vegetatian type carefully.
I had success with Malawans like Fossorochromis over sand substrate riddled with Valls, and Tanganyikans such as Lepidiolamprologus with Vals., and Anubius.


My nitrate conscentrations, are usually undedectable, but I allow leaf litter to buid up to supply food to the rooted plants .
I have also been able to keep Crypts with cichlids (don´t remember what species), as long as the roots had a sufficient time to thoughly establish themselves.
With these Crypts (below) the tank was allowed 2 months before cichlids were added, and the roots had an extensive thick matt, by then.

But I agree, with DJRamsome, most of the colorful Malawans available are probably not going to easily fit into your planted scenario.

Above Cribroheros rostratum (Central American eartheaters) with Crypts and Vals.
