I haven't grown swamp sunflower, but I wonder if it would enjoy the dry heat of SoCal. There are some dry climate sunflowers that might be better adapted to hot SoCal (Encelia californica, Helianthus maximiliani, to name a few). Are you referring to growing these by a real pond, possibly with varying water levels, or a plastic/liner/hardscape pond marginal area?

I've grown Joe Pye in full sun without any special cultural care. A gopher seemed to be crazy for the plant--eating the root of one, then tunneling 45' past a variety of other garden offerings, to gnaw on the roots a second plant. I don't know if that was typical behavior, or just that individual's taste bud's delight! They seemed to be short-lived plants in my garden--2-3 years tops--but several seedlings would come up to replace the parents, so it wasn't a problem. The newer, shorter cultivars didn't reseed for me when I grew them

I haven't grown that particular lobelia that I recall, but it is Sunset zone rated 4-9. 14-24, so it should do fine in San Diego. Sunset recommends a sunny, wind-sheltered position in fertile, well-drained soil. Regular irrigation.