Guilds for Potted Trees?

I live in zone 5b in the US, and we have sub zero temperatures (F) in the winter. I am slowly building a collection of potted trees that go inside shelter in the winter and out on the patio in the warmer months. Right now its just a single Valencia Orange tree, but I hope to add Lemon, Lime, Grapefruit, Banana, Pineapple (not really a tree but still a perinnial), Cocao, Vanilla (another non-tree perinnial), and olive trees to my potted orchard collection.

I would repot the trees every 2-3 years, either to a larger pot, or to renew their soil with fresh nutrients. With permaculture being lazy farming and all, I would prefer to use guilds to keep the potted soil healthy and renewed without constantly adding compost or repotting. What plants would you recommend I try in the pot with the orange tree?

Thanks in advance for your advice!

Two plants that I can think of are coriander (cilantro) and nasturtium. I have potted avocados and citrus in the ground (which I put up a winter greenhouse around), and the cilantro and nasturtium have worked well as understory plants with them.

Thank you for the suggestions! I have cilantro seeds in my seed box, but I will have to get the Nasturtium. Their little orange flowers will look sharp in the pot with the little oranges.