1. Preheat grill to medium-high heat (350° to 400°). Melt butter in a small saucepan; stir in oil.
2. Brush corn, zucchini, and onion with half the oil-butter mixture, and place on greased grill grate. Place bacon strips off to the side on grate.
3. Grill corn 8 to 10 minutes, onion 8 minutes, and zucchini 5 to 7 minutes, turning and basting all vegetables several times; remove vegetables as they are done. Grill bacon about 5 minutes on each side. Remove bacon, and set aside with vegetables until cool enough to handle.
4. Add tomatoes to grill; grill 3 to 5 minutes, basting with remaining oil-butter mixture.
5. Cut kernels from corn, and place in a large bowl. Chop zucchini, onion, and bacon; add to bowl. Stir in tomatoes and lima beans.
6. Stir together vinegar and next 3 ingredients. Pour over succotash; toss well.