Those plants are forget-me-nots they are wild flowers in Wisconsin, but I think you can get them at a lot of plant nurseries. Specifically they are water forget-me-nots. I couldn't find any pics online, but northern Wisconsin they are all along the edge of every stream. Thick mats full of little blue flowers. They grow on the muddy shore and into the water so they are almost fully submerged except for their tips. They would probably make great "edge of pond" plant. They are considered bog plants.
Pic
My forget-me-nots flower easily, but they have to grow to the top of the tank first. It seems they like to be a certain height before flowering. I think theres a purple violet in there, it flowered once but I don't think it cares for the all the moisture.
$2 was a good deal, but it came with about 50 dead ladybugs.
No the shrimp won't leave the water. The toad always stares at the water though. Watching the fish, shrimp, and snails. Occasionally he goes for them, but ends up just going for a swim. Its important to keep the water level very close to the top of the wall so he is able to get back out.
There is no electric filtration in the tank. The plants will/do filter the water they way they do in nature. Any ammonia is consumed by them. The waterfall is turned on very rarely, usually only to add extra water to the soil side of the tank. Currently its too over grown to work. Usually the stream bed fills with roots and plants. The waterfall hasn't been on in over a month, when it is on its only for a hour or two. I haven't had any problems with the water having no movement. It does get that oily layer on the surface, like some tanks do. Its very minor though, I think the snails and fry eat it.
My waterfall is rarely used, because the pump cord is 5" too short to reach the power strip. Those little things you over look

. The plan was to set it on a timer so it came on occasionally during the day.