Not sure about okra, but the tomatoes, cukes, eggplant and peppers will all grow together well. Just space properly, 3-4 sq ft per plant.

I've grown sweet peppers and eggplant together without a problem. Currently I'm growing some green peppers with sugar snap peas. I plan on adding some sweet peppers and basil to that system as well. they'll all be running at a concentration of approximately 650 ppm. I'm not sure how much the green peppers or basil will like that, but I know the peas and the sweet peppers should be fine. I wouldn't grow tomatoes with them though as they're heavy feeders and take a higher concentration (currently 900(-)ppm)