They are cumulative, grab the VC-6.0.0U1-Appliance patch (build 3018521) and it will include all previous VCSA 6.0 updates.
Incidentally once you install the U1 patch you will then be able to install subsequent updates via the web interface again via https://<yourVSA>:5480, the 'VAMI' has been rewritten from scratch and is now back