For the Vista Extended Kernel, the actual intended update path is 2017 EOS + SHA-2 update. The 2018 rollup sometimes suggested is to get a base no updates install up and working with the kernel, but the path that it was changed to however long ago is just the 2017 EOS + SHA-2 update.
Also the extended kernel does have some issues with certain applications. I think I prefer the VxKex style of kernel extension where no system files are touched and it redirects functions. Although I think the Vista Extended Kernel type extension would be more compatible with non-native applications.