I heard that marigolds are good companion plants and help keep pests down. I do not believe they are good for cutting.

Calendula - commonly called Pot Marigold but not a true Marigold - says on my packet that it's good for cut flowers, blooms are edible, and long-lasting. It's often recommended in veggie gardens. I have two coming up in my SFG now from seed, and just budding. We shall see! Actual Marigold (Tagetes patula is the one I have) is also good in the garden and also attracts beneficial insects etc.

Calendula says full sun but you could try in 4-5 hours and see if they work? (I'm a newbie). ;)

zinnias, gladiolus, freesia, etc

They should all still grow well within this growing season.

Also, any of those tall plants with flower spikes, like larkspur, foxtrot, etc but they may take a while longer to establish a bloom.

I have space for Zinnias and cosmos which are good for cutting. You could do a taller marigold. I've never put lavender in myself but I don't see why it wouldn't make a good dual purpose plant.