Hi all,
I agree with MickDK think the first plant is a Selaginella sp., and as suggested they don't do well underwater long term, although they are very good for terrariums etc.
I'm not convinced the second one is Crassula helmsii, the leaf whorls don't look quite right, I'm pretty sure that C. helmsii has leaves in pairs that are opposite, with each new leaf pair at 90o from the one immediately below it. Having said that I don't what it is.
The stalked flowers and whorled leaves look a bit like a Pearlwort (Sagina spp.).
cheers Darrel