I only know 3 classic approaches to translations regardless of scale also we only have 3 possible modi operandi
post processing
pre has the problem of flexibility and missing cases
So those are the classic trades we can mix them to some degree as you know but in my experience those are the obvious problems of each application. And you need to find a process that works good for your team.
About the solutions:
Personally I worked with the first two technologies and with all 3 operational modi.
If you ask me what is best .... I don't know the only thing I am pretty sure is that you should start with a base language where you easily get translators so you only use 1 level of semantics between languages.
These are my only thoughts atm.
The frequency is not the issue, the coverage can be on the other hand if you give your translators and services the right tools this can be easy and efficient.
The problem with any system is state to time where you would need to track the current version + translations catalog just to be sure.
Also the next questions are mixed stacks who make this problem even more interesting.
about VCS maybe don't make a release tag :) just do the checkout and rsync the files to a package folder? without vcs? I know it's hacky .... just thinking out loud