bitbit,
Those are great choices. The heliotrope will need a fair amount of direct sun to get a nice display of flowers. The flower clusters hang on for a long time, but do deadhead it to promote new blooms. Also, with the heliotrope, avoid getting the foliage wet. They do best with evenly moist soil.
Here's some I started from seed last year. I had 3 plants of heliotrope Dwarf Benary's Marine and other annuals in a wooden barrel.
You may want to consider the geraniums. I love both zonal and ivy geraniums. Calliope (specialty geranium) is my fave. I plant it in ground, in planters and also in baskets. I think they would do well in the conditions explained. I have never had luck with torenia.
