those tools are for one purpose only - to hold the inner tube still while removing the allen bolt from the bottom. In most cases, if the inner tube is not held with one of those tools (or a homemade version of those tools) it will just turn with the allen bolt. The 4 in your pic are just different versions of the same basic tool.
not having a 650CSR I cant really comment on the "little plastic thingies" of which you speak. hopefully someone else can/will chime in on that subject.
