1) Please refer to Component version states section of PSoC Creator User Guide: https://www.cypress.com/file/137441/download
2) It is always recommended to use the latest component versions, since bugs present in the previous versions would be be fixed in the latest versions.
I understood that "downloadable" means the components under development but it it available and may include bugs.
And the latest component versions means the components without downloadable, right?
Downloadable means that it is not already installed and is available online.
So, you need to connected to internet to update to "downloadable" components.
The versions are named in ascending order. So, in your case, CapSense V6.0 is the latest one that has many bug fixes and hence, it is recommended to use V6.0