Light, Carbon, Iron, general healthy NPK levels, other micros, in rough order of importance.
That said, taken to severe extremes any of these could be rather bad. Also neither plant requires a high-light CO2 injected tank, although you will get deeper reds by overdriving the plant a bit in one...
The flourish tabs should cover you in micros pretty well, and provide a little bit of NPK. I'm not sure what's in your iron root tabs, never seen an iron-only product before. Regardless, it sounds like it should have sufficient iron, and the flourish would provide more.
So, it looks like light, carbon and NPK are the things I'd review.