No issues with tank size, but you can't keep parrots with Malawi cichlids for plenty of other reasons unfortunately.
First problem is they need different parameters. Malawi mbuna need hard very alkaline water with a pH range for 7.8 to 8.6 whereas the parrots come from a different continent and need medium hard water with a pH range from 6.5 to 7.5. There's no overlap at all.
The second major problem is dietary. Mbuna are herbivores but parrots are omnivores whose diet needs to include a good proportion of animal protein, live foods and so on which are actually harmful to mbuna causing bloat.
EDIT: Cross-posted, sorry!