I agree with you that the ESXi patch terminology and versioning are very confusing.
What you need to be aware of is that ESXi patches are cumulative - they always update the entire esx-base VIB package. This means Patch 10 includes not only the fixes it was developed for, but also all fixes from patch 1-9. This includes any earlier "express" patches. There is no need to apply earlier esx-base patches prior to updating to the latest package because all fixes are included in the full cumulative package anyways.
I would just get the latest Cisco offline bundle which includes other packages like drivers and update to this version:
https://my.vmware.com/web/vmware/details?downloadGroup=OEM-ESXI55U3B-CISCO&productId=353
And then update to the latest ESXi patches. You can apply any normal VMware ESXi patches on top of specific ISO installations because 3rd party vendors like Cisco, HP, Dell etc do not modify any actual ESXi code. They just add management extensions and update drivers to specificially support their hardware. Anyone can create identical ISOs by grabbing all the individual packages from VMware and the vendors and combine them together in one ISO/offline bundle.
The ESXi build number (vmware -vl) corresponds to the esx-base VIB version (esxcli software vib list | grep base). You can check which current patch level you have by matching the build number against this list:
Build numbers and versions of VMware ESXi/ESX (2143832) | VMware KB