yes, that certainly does look like a Buddhas temple crassula, that bottom left tower shaped plant. The second and third top plants look like they may be crassula ericoides. I can't be too sure on the species, because some that look exactly alike could be different species. I usually just go by the genus when I ID plants.
Also, there is nothing wrong with the coloured gravel, I think it makes it look pretty! :)
I daresay that the person who OP bought the plants from may be a bit of a crassula fan. The seller should know the proper species names for the plants, because plant breeders/propagators usually have a good knowledge of the types of plants they grow. Kind of like, you remember the names of your kids, so as a breeder, the first thing you should do is have the correct (or as close to correct) name for the plants you sell to people.