I vote, use other pots. For one thing, I don't think other plants will take well in the established roots of the lemons.
Mint, if happy, is very aggressive, as you may know.
I do think it can be pretty having other plants potted to fill some of that empty space. And they may even shade the pot a little.
And, I don't beleive in companion plants being very effective at pest control or enhancing the soil in a pot.
Let's see what others say
